Nitrile compounds useful as reversible inhibitors of #9 cathepsin 5

ABSTRACT

Disclosed are cathepsin S reversible inhibitory compounds of the formulas (I),(Ia) and (II),(IIa) as defined herein. The compounds are useful for treating autoimmune diseases. Also disclosed are processes for making such novel compounds.

RELATED APPLICATIONS

The benefit of prior provisional application Ser. No. 60/122,570, filed on Mar. 2, 1999, is hereby claimed.

TECHNICAL FIELD OF THE INVENTION

This invention relates to peptidyl cysteine protease inhibitors. The compounds are reversible inhibitors of the cysteine protease cathepsin S and are therefore useful in the treatment of autoimmune diseases. The invention also relates to processes for preparing such compounds and pharmaceutical compositions comprising them.

BACKGROUND OF THE INVENTION

Cathepsin S is a member of the papain family, within the papain superfamily of cysteine proteases. The papain family is the largest group of cysteine proteases and includes proteases such as cathepsins B, H, K, L, O and S. (A. J. Barrett et al., 1996, Perspectives in Drug Discovery and Design, 6, 1). The cysteine proteases have important roles in human biology and diseases including atherosclerosis, emphysema, osteoporosis, chronic inflammation and immune disorders (H. A. Chapman et al., 1997, Ann. Rev. Physiol., 59, 63). Cathepsin S plays a key role in regulating antigen presentation and immunity (H. A. Chapman, 1998, Current Opinion in Immunology, 10, 93; R. J. Riese et al., 1998, J. Clin. Invest., 101, 2351; R. J. Riese et al., 1996, Immunity, 4, 357).

The specificity of the immune response relies on processing of foreign protein and presentation of antigenic peptide at the cell surface. Antigenic peptide is presented bound to MHC Class II, a heterodimeric glycoprotein expressed in certain antigen presenting cells of hematopoietic lineage, such as B cells, macrophages and dendritic cells. Presentation of antigen to effector cells, such as T-cells, is a fundamental step in recognition of non-self and thus initiation of the immune response.

Recently MHC Class II heterodimers were shown to associate intracellularly with a third molecule designated invariant chain. Invariant chain facilitates Class II transport to the endosomal compartment and stabilizes the Class II protein prior to loading with antigen. Invariant chain interacts directly with Class II dimers in the antigen-binding groove and therefore must be proteolyzed and removed or antigen cannot be loaded or presented. Current research suggests that invariant chain is selectively proteolyzed by cathepsin S, which is compartmentalized with MHC Class II complexes within the cell. Cathepsin S degrades invariant chain to a small peptide, termed CLIP, which occupies the antigen-binding groove. CLIP is released from MHC Class II the interaction MHC Class II with HLA-DM, a MHC-like molecule thus freeing MHC Class II to associate with antigenic peptides. MHC Class II-antigen complexes are then transported to the cell surface for presentation to T-cells, and initiation of the immune response. Cathepsin S, through proteolytic degradation of invariant chain to CLIP, provides a fundamental step in generation of an immune response. It follows that inhibition of antigen presentation via prevention of invariant chain degradation by cathepsin S could provide a mechanism for immuno-regulation. Control of antigen-specific immune responses has long been desirable as a useful and safe therapy for autoimmune diseases. Such diseases include Crohn's disease and arthritis, as well as other T-cell-mediated immune responses (C. Janeway and P. Travers, 1996, Immunobiology, The Immune System in Health and Disease, Chapter 12). Furthermore, cathepsin S, which has broad pH specificity, has been implicated in a variety of other diseases involving extracellular proteolysis, such as Alzheimer's disease (U. Muller-Ladner et al., 1996, Perspectives in Drug Discovery and Design, 6, 87) and atherosclerosis (G. K. Sukhova et al., 1998, J. Clin. Invest., 102, 576).

Cysteine proteases are characterized by having a cysteine residue at the active site which serves as a nucleophile. The active site also contains a histidine residue. The imidazole ring on the histidine serves as a base to generate a thiolate anion on the active site cysteine increasing its nucleophilicity. When a substrate is recognized by the protease, the amide bond to be cleaved is directed to the active site, where the thiolate attacks the carbonyl carbon forming an acyl-enzyme intermediate and cleaving the amide, liberating an amine. Subsequently, water cleaves the acyl-enzyme species regenerating the enzyme and liberating the other cleavage product of the substrate, a carboxylic acid.

A proposed mechanism of action of the cysteine protease inhibitors of this invention is that the inhibitors contain a functionality that can react (reversibly or irreversibly) with the active site cysteine. The reactive functionality is attached to a peptide or peptide mimic that can be recognized and accommodated by the region of the protease surrounding the active site. The nature of both the reactive functionality and the remaining portion of the inhibitor determine the degree of selectivity and potency toward a particular protease.

Examples of reactive functionalities that have been described (D. Rasnick, 1996, Perspectives in Drug Discovery and Design, 6, 47) on cysteine protease inhibitors include peptidyl diazomethanes, epoxides, monofluoroalkanes and acyloxymethanes, which irreversibly alkylate the cysteine thiol. Other irreversible inhibitors include Michael acceptors such as peptidyl vinyl esters and other carboxylic acid derivatives (S. Liu et al., J. Med Chem., 1992, 35, 1067) and vinyl sulfones (J. T. Palmer et al., 1995, J. Med Chem., 38, 3193).

Reactive functionalities that form reversible complexes with the active site cysteine include peptidyl aldehydes (R. P. Hanzlik et al., 1991, Biochim. Biophys. Acta., 1073, 33), which are non-selective, inhibiting both cysteine and serine proteases as well as other nucleophiles. Peptidyl nitriles (R. P. Hanzlik et al., 1990, Biochim. Biophys. Acta., 1035, 62) are less reactive than aldehydes and therefore more selective for the more nucleophiles cysteine proteases. Various reactive ketones have also been reported to be reversible inhibitors of cysteine proteases D. Rasnick, 1996, ibid). In addition to reacting with the nucleophilic cysteine of the active site, reactive ketones may react with water, forming a hemiketal which may act as a transition state inhibitor.

Examples of cathepsin S inhibitors have been reported previously. J. T. Palmer (U.S. Pat. No. 5,776,718, 1998) described reversible peptidyl sulfones as inhibitors of cysteine proteases including cathepsin S. J. L. Klaus et al. (WO 9640737, 1996) described reversible inhibitors of cysteine proteases including cathepsin S, containing an ethylene diamine.

Additional peptidyl nitrites or peptidyl ketoheterocyles have been reported either as protease inhibitors or as having other utilities. For example, both nitrites and ketoheterocycles are described by B. A. Rowe et al. (U.S. Pat. No. 5,714,471, 1998) as protease inhibitors useful in the treatment of neurodegenerative diseases. Peptidyl nitriles are reported by B. Malcolm et al. (WO 9222570, 1992) as inhibitors of picornavirus protease. H. Saika et al. (WO 9512611, 1995) report peptidyl nitrites among compounds having endothelin receptor antagonist activity. B. J. Gour-Salin (Can. J. Chem., 1991, 69. 1288) and T. C. Liang (Arch. Biochim. Biophys., 1987, 252, 626) described peptidyl nitrites as inhibitors of papain. D. W. Woolley et al. (J. Org. Chem., 1963, 28, 2012) described a peptidyl nitrile as a chemical intermediate.

Peptidyl ketoheterocycles having protease inhibiting or other activities have been reported, include inhibitors of serine proteases described by R. D. Tung et al. (WO 9817679, 1998). Inhibitors of Factor X_(a) have been described by C. K. Marlowe et al. (WO 9640744, 1996). Peptidyl ketoheterocycles useful in the treatment of thrombin related diseases have been described by M. Costanzo et al. (WO 9640742, 1996).

A reversible inhibitor presents a more attractive therapy than irreversible inhibitors. Even compounds with high specificity for a particular protease can bind non-target enzymes. An irreversible compound could therefore permanently inactivate a non-target enzyme, increasing the likelihood of toxicity. Furthermore, any toxic effects resulting from inactivation of the target enzyme would be mitigated by reversible inhibitors, and could be easily remedied by modified or lower dosing. Finally, covalent modification of an enzyme by an irreversible inhibitor could potentially generate an antibody response by acting as a hapten.

In light of the above, there is a clear need for compounds which reversibly and selectively inhibit cathepsin S, such inhibitors would be useful in therapy for antigen-specific immune responses as well as for indications in which cathepsin S exacerbates disease through extracellular activity.

BRIEF DESCRIPTION OF THE INVENTION

The work cited above supports the principle that inhibition of cathepsin S and subsequent inhibition of antigen presentation will be beneficial in the treatment of various disease states. It is therefore an object of this invention to provide novel compounds that inhibit antigen presentation by virtue of reversible inhibition of the cysteine protease cathepsin S. It is a further object of the invention to provide methods for treating diseases and pathological conditions involving immune disorders such as rheumatoid arthritis. It is yet a further object of the invention to provide processes for preparation of the above-mentioned novel compounds.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides novel compounds of the formula (I):

A is —C(Y)— or —SO₂—

Y is O, S or NR_(a) wherein R_(a) is selected from the group consisting of H, alkyl, aryl, alkoxy, aryloxy alkylamino and arylamino;

R₁ is alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl or amino wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkoxy, aryloxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyl, aroyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocycle, heteroaryl, arylalkyl, alkoxy, aryloxy, arylalkoxy, alkanoyl, aroyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₂ is H or alkyl,

R₃ is H, alkyl, cycloalkyl, aryl, heterocyclyl or heteroaryl, wherein R₃ is optionally substituted by one or more groups of the formula R_(d);

R_(d) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkoxy, aryloxy, arylalkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyl, aroyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of alkyl, cycloalkyl, aryl, arylalkyl, alkoxy, aryloxy, arylalkoxy, alkanoyl, aroyl, amino, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₄ is H or alkyl;

R₅ is H, alkyl or cycloalkyl;

R₆ is H, alkyl, cycloalkyl, aryl, heterocyclyl or heteroaryl, wherein R₆ is optionally substituted by one or more groups of the formula R_(f);

R_(f) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkoxy, aryloxy, alkanoyl, aroyl, arylalkoxy, heteroarylalkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylalkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of alkyl, cycloalkyl, aryl optionally substituted by halogen, C1-5alkyl or C1-5alkoxy, heterocyclyl, heteroaryl, alkoxy, aryloxy, arylalkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl; alkanoylamino, aroylamino, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl heterocyclyl or heteroaryl; alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl; halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

or R₅ together with R₆ form a 3 to 6 membered carbocyclic ring, the carbocyclic ring being optionally substituted with one or more R_(h);

R_(h) is selected from the group consisting of alkyl, aryl, alkoxycarbonyl, aryloxycarbonyl, arylalkoxycarbonyl, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with a group selected from alkyl, cycloalkyl, aryl, arylalkyl, heterocyclyl or heteroaryl halogen, hydroxy, carboxy and cyano;

R₇ is R₈—C(Z)—;

wherein Z is O, S, or NR_(i) wherein R_(i) is selected from the group consisting of H, alkyl, aryl, alkoxy, aryloxy and hydroxy;

R₈ is a 5-8 membered monocyclic heteroaryl or 8-11 membered bicyclic heteroaryl ring system, each of the monocyclic or bicyclic ring systems having 1-4 of the same or different heteroatoms selected from the group consisting of N, O and S wherein any of the above R₈ can be optionally substituted by one or more R_(j);

R_(j) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, arylalkyl, alkoxy, aryloxy, alkanoyl, aroyl, arylalkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylalkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl or heteroaryl; alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl; halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(j) may be further optionally substituted by one or more R_(k);

R_(k) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkoxy, aryloxy, arylalkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkoxycarbonylamino, aryloxycarbonylamino, arylalkoxycarbonylamino, arylalkoxycarbonylaminoalkyl, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

X is O, S or N—OH;

and the pharmacurtically acceptable derivatives thereof;

with the proviso that when R₆ is alkyl the alkyl must be substituted with R_(f) wherein R_(f) is not hydroxy, sulfhydryl or halogen.

Preferred compounds of the formula (I) are those wherein:

R_(a) is selected from the group consisting of H, alkyl and aryl;

R₁ is C1-8 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, pyranyl, thiopyranyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, or amino wherein R1 is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-8 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, C1-8 alkoxycarbonyl, aryloxycarbonyl, C1-8 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkanoylamino, aroylamino, C1-8 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, C1-8 alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-8 alkyl, C3-6 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₃ is H, C1-8 alkyl, C3-7 cycloalkyl or aryl wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C1-8 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, alkanoyl, aroyl, C1-8 alkoxycarbonyl, aryloxycarbonyl, C1-8 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkanoylamino, aroylamino, C1-8 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, C1-8 alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-8 alkyl, C3-6 cycloalkyl, aryl, arylalkyl, C1-8 alkoxy, aryloxy, arylalkoxy, aroyl, amino, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₅ is H or alkyl;

R₆ is H, C1-8 alkyl, C3-7 cycloalkyl or aryl wherein R₆ is optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of C1-8 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, arylC1-8alkoxy, heteroarylC1-8alkoxy, C1-8 alkoxycarbonyl, aryloxycarbonyl, C1-8 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkanoylamino, aroylamino, C1-8 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylC1 -8 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, C1-8 alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-8 alkyl, C3-7 cycloalkyl, aryl optionally substituted by halogen, C1-3alkyl or C1-3alkoxy; heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, arylC1-8alkoxy, C1-8 alkoxycarbonyl, aryloxycarbonyl, C1-8 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkanoylamino, aroylamino, C1-8 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl or phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, C1-8 alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl and arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R_(h) is selected from the group consisting of C1-8 alkyl, aryl, C1-8 alkoxycarbonyl, aryloxycarbonyl, arylC1-8alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with a group selected from C1-8 alkyl, C3-7 cycloalkyl, aryl, arylC1-8alkyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, carboxy and cyano;

R₈ is a heteroaryl ring selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, indolizinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, indazolyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, triazolyl, tetrazolyl, purinyl, quinolizinyl, quinolinyl, isoquinolinyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, naphthyridinyl, pteridinyl, carbazolyl, acridinyl and phenazinyl, wherein any of the above R₈ can be optionally substituted by one or more R_(j);

R_(j) is selected from the (group consisting of alkyl, cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, arylalkyl, alkoxy, aryloxy, arylalkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkanoylamino, aroylamino, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylalkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, C1-8 alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(j) may be further optionally substituted by one or more R_(k);

R_(k) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxy, aryloxy, arylalkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkanoylamino, aroylamino, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinylor heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, arylalkoxycarbonylamino, arylalkoxycarbonylaminoalkyl, C1-8 alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinylor heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

X is O or S.

More preferred compounds of the formula (I) are those wherein:

Y is O or S;

R₁ is C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, pyranyl, thiopyranyl, piperazinyl and indolinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl or amino wherein R1 is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-5 alkyl, C3-6 cycloalkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl and pyridinyl, C1-5 alkoxy, aryloxy, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₂ is H or C1-3 alkyl;

R₃ is H, C1-5 alkyl, C3-7 cycloalkyl or aryl, wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, C1-5alkanoyl, aroyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinylor heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(d) may be further optionally substituted by one or more R_(c);

R_(e) is selected from the group consisting of C1-5 alkyl, C3-6 cycloalkyl, aryl, arylalkyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, aroyl, amino, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₄ is H or C1-3 alkyl;

R₅ is H or C1-8 alkyl;

R₆ is H, C1-5 alkyl, C3-7 cycloalkyl or aryl wherein R₆ is optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, heteroarylC1-5alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylC1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, aryl optionally substituted by halogen, methyl or methoxy; heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R_(h) is selected from the group consisting of C1-5 alkyl, aryl, C1-5 alkoxycarbonyl, aryloxycarbonyl, arylC1-5alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with a group selected from C1-5 alkyl, C3-7 cycloalkyl, aryl, arylC1-5alkyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, carboxy and cyano;

R_(j) is alkoxy, aryloxy or hydroxy;

R₈ is a heteroaryl ring selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, indolizinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, indazolyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolizinyl, quinolinyl, isoquinolinyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, naphthyridinyl, pteridinyl, carbazolyl, acridinyl and phenazinyl, wherein any of the above R₈ can be optionally substituted by one or more R_(j);

R_(j) is selected from the group consisting of C1-8alkyl, C3-7cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl; arylC1-8alkyl, C1-8alkoxy, aryloxy, arylC1-8alkoxy, C1-8alkoxycarbonyl, aryloxycarbonyl, C1-8alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8alkanoylamino, aroylamino, C1-8alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylC1-8alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, C1-8 alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(j) may be further optionally substituted by one or more R_(k);

R_(k) is selected from the group consisting of C1-8 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, arylC1-8alkoxy, C1-8alkoxycarbonyl, aryloxycarbonyl, C1-8alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkanoylamino, aroylamino, C1-8alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-8alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinylor heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8alkoxycarbonylamino, aryloxycarbonylamino, arylC1-8alkoxycarbonylamino, arylalkoxycarbonylamino C1-8alkyl, C1-8 alkylcarbamoyloxy, arylcarbamoyloxy, C1-8alkylsulfonylamino, arylsulfonylamino, C1-8alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-8alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino.

Even more preferred compounds of the formula (I) are those wherein:

Y is O;

R₁ is C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl, pyranyl and thiopyranyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, or amino wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl; C1-5 alkoxy, aryloxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl or aryl; C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy, cyano and nitro, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-5 alkyl, C3-6 cycloalkyl, aryl, C1-5 alkoxy, aryloxy, halogen, hydroxy, oxo, carboxy, and cyano;

R₂ is H or methyl;

R₃ is H, C1-5 alkyl, C3-7 cycloalkyl or phenyl, wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxy, aryloxy, aroyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-5 alkyl, C3-6 cycloalkyl, aryl, arylC1-5 alkyl, C1-5 alkoxy, aryloxy, arylC1-3alkoxy, aroyl, amino, halogen, hydroxy, oxo, carboxy and cyano;

R₄ is H or methyl;

R₅ is H or C1-5 alkyl;

R₆ is H, C1-5 alkyl, C3-7 cycloalkyl, phenyl or naphthyl wherein R₆ is optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, pyridylC-5alkoxy, thienylC1-5alkoxy, furanylC1-5alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylC1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano, Rf may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, phenyl optionally substituted by halogen, methyl or methoxy; naphthyl optionally substituted by halogen, methyl or methoxy; heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano;

R_(h) is selected from the group consisting of C1-5 alkyl, phenyl, naphthyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, arylC1-3alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with a group selected from C1-5 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, arylC1-3alkyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, carboxy and cyano;

Z is O or S;

R₈ is a heteroaryl ring selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, indolizinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, indazolyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolizinyl, quinolinyl, isoquinolinyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, naphthyridinyl, pteridinyl, carbazolyl, acridinyl and phenazinyl, wherein any of the above R₈ can be optionally substituted by one or more groups of the formula R_(j);

R_(j) is selected from the group consisting of C1-5alkyl, C3-6cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, arylC1-5alkyl, C1-5alkoxy, aryloxy, arylC1-5alkoxy, C1-5alkoxycarbonyl, aryloxycarbonyl, C1-5alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinylor heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5alkanoylamino, aroylamino, C1-5alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylC1-5alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5alkylsulfonylamino, arylsulfonylamino, C1-5alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(j) may be further optionally substituted by one or more R_(k);

R_(k) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, tetrazolyl and pyridinyl, C1-3 alkoxy, aryloxy, arylC1-3 alkoxy, C1-3alkoxycarbonyl, aryloxycarbonyl, C1-3alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl, aryl, heterocyclyl selected from the group consisting of morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, and pyridinyl, C1-3alkanoylamino, aroylamino, C1-3alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-3alkyl, phenyl, naphthylor heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl and pyridinyl, C1-3alkoxycarbonylamino, aryloxycarbonylamino, arylC1-3alkoxycarbonylamino, benzyloxycarbonylaminoC1-5alkyl, C1-3alkylcarbamoyloxy, arylcarbamoyloxy, C1-3alkylsulfonylamino, arylsulfonylamino, C1-3alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolylpyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy, cyano and nitro; and

X is O.

Yet even more preferred compounds of the formula (I) are those wherein:

R₁ is C1-5 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl, piperazinyl, pyranyl and thiopyranyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, or amino, wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-3 alkoxy, phenoxy, C1-3 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenylor heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5alkyl, phenyl or naphthyl; C1-5 alkoxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, aryl, C1-3 alkoxy, phenoxy, halogen, hydroxy, oxo, carboxy and cyano;

R₂ is H;

R₃ is C1-5 alkyl, C3-6 cycloalkyl or phenyl, wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, quinolinyl and isoquinolinyl, C1-5 alkoxy, phenoxy, aroyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, C1-5 alkanoylamino, aroylamino, C1-3 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, phenylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-3 alkyl, phenyl or heteroaryl selected the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl C1-5 alkoxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl, phenyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-5 alkyl, C5-6 cycloalkyl, phenyl, naphthyl, arylC1-3alkyl, C1-5 alkoxy, phenoxy, arylC1-3alkoxy, aroyl, amino, halogen, hydroxy, oxo, carboxy and cyano;

wherein the configuration at the stereocenter defined by R₂ and R₃ and the carbon they are attached to is L;

R₄ is H;

R₅ is H or C1-3 alkyl;

R₆ is H, C1-5 alkyl, C3-6 cycloalkyl or phenyl, wherein R₆ is optionally substituted by one or more R_(f),

R_(f) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxy, aryloxy, arylC1-3alkoxy, pyridylC1-5alkoxy, thienylC1-5alkoxy, furanylC1-5alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenylor heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, C1-5 alkanoylamino, aroylamino, C1-3 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylC1-3alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl or phenyl; C1-5 alkoxycarbonylamino, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, halogen, hydroxy, oxo, carboxy and cyano, Rf may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, phenyl optionally substituted by halogen, methyl or methoxy; heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, pyrimidinyl, pyrazinyl and indolyl, C1-5 alkoxy, aryloxy, arylC1-3alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or aryl; C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl or aryl; C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or aryl; halogen, hydroxy, oxo, carboxy and cyano;

R_(h) is selected from the group consisting of C1-5 alkyl, phenyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, arylC1-3alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with C1-5 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, arylC1-3alkyl, halogen, hydroxy, carboxy and cyano;

wherein Z is O;

R₈ is a heteroaryl ring selected from the group consisting of oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, wherein any of the above R₈ can be optionally substituted by one or more R_(j);

R_(j) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, phenyl, naphthyl, morpholinyl, piperazinyl, furanyl, thienyl, pyrrolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, arylC1-3alkyl, C1-3alkoxy, aryloxy, arylC1-3alkoxy, C1-3alkoxycarbonyl, aryloxycarbonyl, C1-3alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3alkyl, phenyl, naphthyl, piperidinyl, furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl or isoquinolinyl; C1-3alkanoylamino, aroylamino, C1-3alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylC1-3alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-3 alkyl, phenyl, naphthyl, piperidinyl, morpholinyl, thiazolyl imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl or isoquinolinyl; C1-3 alkoxycarbonylamino, aryloxycarbonylamino, C1-3 alkylcarbamoyloxy, arylcarbamoyloxy, C1-3alkylsulfonylamino, arylsulfonylamino, C1-3alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl, phenyl, naphthyl, piperidinyl, furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl or isoquinolinyl; halogen, hydroxy, oxo, carboxy, cyano and nitro, R_(j) may be further optionally substituted by one or more R_(k);

R_(k) is selected from the group consisting of methyl, C5-6 cycloalkyl, phenyl, morpholinyl, furanyl, thienyl, pyrrolyl, tetrazolyl, pyridinyl, methoxy, phenoxy, benzyloxy, methoxycarbonyl, acetyloxy, benzoyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl, phenyl, furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl or pyridinyl; acetylamino, benzoylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by methyl, phenyl, furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl or pyridinyl; arylC1-3alkoxycarbonylamino, benzyloxycarbonylaminoC1-5alkyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3alkyl, phenyl, naphthyl, furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl or isoquinolinyl, halogen, hydroxy, oxo, carboxy, cyano and nitro.

Still yet even more preferred compounds of the formula (I) are those wherein:

R₁ is C1-3 alkyl, C5-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl, piperazinyl, pyranyl and thiopyranyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, or amino, wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, phenyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-3 alkoxy, C1-3 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl, phenyl or heteroaryl selected from the group consisting of pyrrolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl and benzthiazolyl; C1-5 alkanoylamino, aroylamino, C1-3 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-3alkyl or phenyl; C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3alkyl, phenyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinylor heteroaryl selected from the group consisting of pyrrolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl; halogen, hydroxy, oxo, carboxy and cyano, R_(b) may be further optionally substituted by one or more R_(c);

R_(c)is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, C1-3 alkoxy, halogen and hydroxy;

R₃ is C1-5 alkyl, C5-6 cycloalkyl or phenyl wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, 4-piperidinyl, 4-morpholinyl, piperazinyl, furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, C1-5 alkoxy, phenoxy, aroyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or phenyl; C1-5 alkanoylamino, C1-3 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-3 alkyl or phenyl; C1-5 alkoxycarbonylamino, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl; halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-5 alkyl, C5-6 cycloalkyl, phenyl, benzyl, C1-5 alkoxy, phenoxy, benzyloxy, aroyl, halogen hydroxy, oxo, carboxy and cyano;

R₆ is H, C1-5 alkyl or phenyl wherein R₆ is optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, C1-3 alkoxy, benzyloxy, pyridyl, C1-3alkoxy, thienylC1-3alkoxy, furanylC1-3alkoxy, C1-3 alkoxycarbonyl, phenoxyoxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl; C1-5 alkanoylamino, aroylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl or phenyl; C1-3 alkoxycarbonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or phenyl; halogen, hydroxy, oxo, carboxy and cyano, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-3 alkyl, phenyl optionally substituted by halogen, methyl or methoxy; heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl and pyridinyl, C1-3 alkoxy, aryloxy, benzyloxy, C1-5 alkoxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or phenyl; C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl or phenyl; C1-5 alkoxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-3 alkylsulfonylamino, arylsulfonylamino, C1-3 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl; halogen, hydroxy, oxo, carboxy and cyano;

R_(h) is selected from the group consisting of C1-3 alkyl, phenyl, C1-3 alkoxycarbonyl, phenoxyoxycarbonyl, benzyloxy, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with C1-5 alkyl, phenyl, benzyl, halogen, hydroxy, carboxy and cyano;

R₈ is a heteroaryl ring selected from the group consisting of oxazolyl, thiazolyl, imidazolyl, pyridyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, wherein any of the above R₈ can be optionally substituted by one or more R_(j);

R_(j) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, phenyl, naphthyl, morpholinyl, piperazinyl, furanyl, thienyl, pyrrolyl, tetrazolyl, pyridinyl, to benzyl, C1-3alkoxy, phenoxy, benzyloxy, C1-3alkoxycarbonyl, acetyloxy, benzoyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by methyl, phenyl, furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl or pyridinyl; acetylamino, benzoylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by methyl, phenyl, thiazolyl, imidazolyl or pyridinyl; C1-3 alkoxycarbonylamino, C1-3 alkylcarbamoyloxy, arylcarbamoyloxy, C1-3alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by methyl, phenyl, furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl or pyridinyl; halogen, hydroxy, carboxy, cyano and nitro, R_(j) may be further optionally substituted by one or more R_(k);

R_(k) is selected from the group consisting of methyl, C5-6 cycloalkyl, phenyl, furanyl, thienyl, pyrrolyl, pyridinyl, methoxy, phenoxy, benzyloxy, methoxycarbonyl, acetyloxy, benzoyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by methyl, phenyl, furanyl or thienyl; acetylamino, benzoylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by methyl, phenyl, furanyl, thienyl, pyrrolyl, oxazolyl and thiazolyl, benzyloxycarbonylamino, benzyloxycarbonylaminoC1-5alkyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3alkyl, phenyl, furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl and pyridinyl, halogen, hydroxy, carboxy, cyano and nitro.

Even much more preferred compounds of the formula (I) are those wherein:

R₁ is C5-6 cycloalkyl, phenyl, naphthyl, piperidinyl, morpholinyl, piperazinyl, furanyl, thienyl, pyrrolyl, pyranyl, thiopyranyl or amino wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, phenyl, furanyl, thienyl, pyrrolyl, imidazolyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, C1-3 alkoxy, C1-3 alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl; C1-5 alkanoylamino, aroylamino, ureido wherein either nitrogen atom may be independently substituted by C1-3alkyl or phenyl; C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3alkyl or phenyl; halogen, hydroxy oxo, carboxy and cyano, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-3 alkyl C1-3 alkoxy, halogen and hydroxy;

R_(d) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, 4-piperidinyl, furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, C1-3 alkoxy, C1-5alkoxycarbonyl, C1-5alkanoyloxy, benzoyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3alkyl or phenyl; C1-5alkanoylamino, C1-3 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, C1-3alkoxycarbonylamino, C1-3alkylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl, halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-3 alkyl, phenyl, benzyl, C1-3 alkoxy, phenoxy, benzyloxy, benzoyl, halogen, hydroxy, oxo, carboxy and cyano;

R₅ is H or methyl;

R₆ is C1-5 alkyl or phenyl, wherein R₆ is optionally substituted by one or more groups of the formula R_(f),

R_(f) is selected from the group consisting of methyl, C3-6 cycloalkyl, phenyl, naphthyl, furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, C1-3 alkoxy, benzyloxy, C1-5 alkanoylamino, aroylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, C1-3 alkoxycarbonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or phenyl; halogen, hydroxy, oxo, carboxy and cyano, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-3 alkyl, phenyl optionally substituted by halogen or methyl; C1-3 alkoxy, aryloxy, benzyloxy, C1-3 alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl; C1-5 alkanoylamino, aroylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl; halogen, hydroxy, oxo, carboxy and cyano;

R_(h) is selected from the group consisting of C1-3 alkyl, phenyl, C1-3 alkoxycarbonyl, benzyloxy and carboxy;

R₈ is a heteroaryl ring selected from the group consisting of oxazolyl, thiazolyl, imidazolyl pyridyl, benzimidazolyl, benzthiazolyl and benzoxazolyl, wherein any of the above R₈ can be optionally substituted by one or more R_(j);

R_(j) is selected from the group consisting of methyl, cyclohexyl, phenyl, furanyl, thienyl, benzyl, methoxy, phenoxy, benzyloxy, methoxycarbonyl, acetyloxy, benzoyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by methyl, phenyl, furanyl or thienyl; acetylamino, benzoylamino, ureido wherein either nitrogen atom may be independently substituted by methyl or phenyl; methoxycarbonylamino, C1-3 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by methyl, phenyl, furanyl or thienyl; halogen, hydroxy, carboxy and cyano, R_(j) may be further optionally substituted by one or more R_(k);

R_(k) is selected from the group consisting of methyl, phenyl, furanyl, thienyl, methoxy, phenoxy, benzyloxy, methoxycarbonyl, acetyloxy, benzoyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by methyl or phenyl; acetylamino, benzoylamino, ureido wherein either nitrogen atom may be independently substituted by methyl or phenyl; benzyloxycarbonylamino, benzyloxycarbonylaminoC1-3alkyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3alkyl, phenyl, furanyl or thienyl; halogen, hydroxy, carboxy, cyano and nitro.

Yet even more preferred compounds of the formula (I) are those wherein:

A is —C(O)— or —SO₂—;

R₁ is cyclohexyl, phenyl, naphthyl, piperidinyl, morpholinyl, piperazinyl, pyranyl, thiopyranyl or amino, wherein R1 is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, phenyl, furanyl, thienyl, pyrrolyl, imidazolyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, C1-3 alkoxy, C1-3 alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl; C1-5 alkanoylamino, aroylamino, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl; halogen, hydroxy, oxo, carboxy and cyano R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-3 alkoxy, halogen and hydroxy;

R₃ is C1-5 alkyl or C5-6 cycloalkyl wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of methyl, C3-6 cycloalkyl, phenyl, thienyl, imidazolyl, pyridinyl, indolyl, C1-4 alkoxy, C1-5 alkanoylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, halogen, hydroxy, oxo, carboxy and cyano R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of methyl, phenyl, benzyl, methoxy, phenoxy, benzyloxy, benzoyl, halogen and hydroxy;

R_(f) is selected from the group consisting of C3-6 cycloalkyl, phenyl, naphthyl, thienyl, imidazolyl, pyridinyl, indolyl, methoxy, benzyloxy, C1-3 alkanoylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, methoxycarbonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl; halogen, hydroxy, carboxy and cyano, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of methyl, phenyl optionally substituted by halogen or methyl; methoxy, phenoxy, benzyloxy, methoxycarbonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl; halogen, hydroxy and carboxy;

R₈ is a heteroaryl ring selected from the group consisting of oxazolyl, thiazolyl, imidazolyl, pyridyl, benzthiazolyl and benzoxazolyl, wherein any of the above R₈ can be optionally substituted by one or more R_(j);

R_(j) is selected from the group consisting of methyl, phenyl, furanyl, thienyl, benzyl, methoxy, methoxycarbonyl, acetyloxy, benzoyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by methyl or phenyl; acetylamino, benzoylamino, ureido wherein either nitrogen atom may be independently substituted by methyl or phenyl; methoxycarbonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by methyl or phenyl; halogen, hydroxy, carboxy and cyano, R_(j) may be further optionally substituted by one or more R_(k);

R_(k) is selected from the group consisting of methyl, phenyl, methoxy, phenoxy, benzyloxy, methoxycarbonyl, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by methyl or phenyl; ureido wherein either nitrogen atom may be independently substituted by methyl or phenyl; benzyloxycarbonylamino, benzyloxycarbonylaminoC1-5alkyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3alkyl, phenyl, furanyl or thienyl; halogen, hydroxy, carboxy, cyano and nitro.

Penultimately preferred compounds of the formula (I) are those wherein:

R₁ is cyclohexyl, phenyl, naphthyl, piperidinyl, morpholinyl, piperazinyl, pyranyl or thiopyranyl, wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of pyrrolyl, imidazolyl, indolyl, benzimidazolyl, methoxy, methoxycarbonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl; halogen, hydroxy and carboxy, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of methoxy, halogen and hydroxy;

R_(d) is selected from the group consisting of methyl, C3-6 cycloalkyl, phenyl, C1-4 alkoxy, C1-3 alkanoylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of methyl, phenyl, methoxy, halogen and hydroxy;

R₅ is H;

R_(f) is selected from the group consisting of C5-6 cycloalkyl, phenyl, naphthyl thienyl indolyl, methoxy, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, methoxycarbonylamino, halogen, hydroxy, carboxy and cyano, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of methyl, phenyl optionally substituted by halogen; methoxy, phenoxy, benzyloxy, methoxycarbonyl, halogen, hydroxy and carboxy;

R₈ is a heteroaryl ring selected from the group consisting of oxazolyl, pyridyl, benzthiazolyl and benzoxazolyl, wherein any of the above R₈ can be optionally substituted by one or more R_(j);

R_(j) is selected from the group consisting of methyl, phenyl, benzyl, methoxy, methoxycarbonyl, acetyloxy, benzoyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by methyl or phenyl; methoxycarbonylamino, halogen, hydroxy and carboxy, R_(j) may be further optionally substituted by one or more R_(k);

R_(k) is selected from the group consisting of methyl, phenyl, methoxy, methoxycarbonyl, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by methyl or phenyl; benzyloxycarbonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by methyl or phenyl; halogen, hydroxy and carboxy.

Ultimately preferred compounds of the formula (I) arc those wherein:

R₁ is phenyl or 4-morpholinyl, wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of benzimidazolyl, methoxy and dimethylamino, R_(b) may be further optionally substituted by a halogen atom;

R₃ is C1-5 alkyl wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C3-6 cycloalkyl and phenyl, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of methyl and halogen;

R₆ is C1-5 alkyl optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of C5-6 cycloalkyl, phenyl, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, and halogen, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of methyl, methoxy, methoxycarbonyl, halogen and hydroxy;

R₈ is a heteroaryl ring selected from the group consisting of oxazolyl, pyridyl, benzthiazolyl and benzoxazolyl, wherein any of the above R₈ can be optionally substituted by one or more R_(k);

R_(j) is selected from the group consisting of phenyl, methoxycarbonyl, carbamoyl wherein the nitrogen atom may be independently mono or disubstituted by methyl or phenyl; methoxycarbonylamino and halogen, R_(j) may be further optionally substituted by one or more R_(k);

R_(k) is selected from the group consisting of phenyl, methoxycarbonyl, carbamoyl, benzyloxycarbonylamino and halogen.

In another embodiment of the invention there are provided novel compounds of the formula (Ia):

wherein:

A is —C(Y)—or —SO₂—

Y is O, S or NR_(a) wherein R_(a) is selected from the group consisting of H, alkyl, aryl, alkoxy, aryloxy, alkylamino and arylamino;

R₁ is alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl or amino wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkoxy, aryloxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyl, aroyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocycle, heteroaryl, arylalkyl, alkoxy, aryloxy, arylalkoxy, alkanoyl, aroyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₂ is H or alkyl;

R₃ is H, alkyl, cycloalkyl, aryl, heterocyclyl or heteroaryl, wherein R₃ is optionally substituted by one or more groups of the formula R_(d);

R_(d) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkoxy, aryloxy, arylalkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyl, aroyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of alkyl, cycloalkyl, aryl, arylalkyl, alkoxy, aryloxy, arylalkoxy, alkanoyl, aroyl, amino, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₄ is H or alkyl;

R₅ is H, alkyl or cycloalkyl;

R₆ is H, alkyl, cycloalkyl, aryl, heterocyclyl or heteroaryl, wherein R₆ is optionally substituted by one or more groups of the formula R_(f);

R_(f) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkoxy, aryloxy, alkanoyl, aroyl, arylalkoxy, heteroarylalkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylalkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of alkyl, cycloalkyl, aryl optionally substituted by halogen, C1-5alkyl or C1-5alkoxy, heterocyclyl, heteroaryl, alkoxy, aryloxy, arylalkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl; alkanoylamino, aroylamino, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl or heteroaryl; alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl; halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

or R₅ together with R₆ form a 3 to 6 membered carbocyclic ring, the carbocyclic ring being optionally substituted with one or more R_(h);

R_(h) is selected from the group consisting of alkyl, aryl, alkoxycarbonyl, aryloxycarbonyl, arylalkoxycarbonyl, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with a group selected from alkyl, cycloalkyl, aryl, arylalkyl, heterocyclyl or heteroaryl; halogen, hydroxy, carboxy and cyano;

R₇ is R₈—C(Z)—;

wherein Z is O, S, or NR_(i) wherein R_(i) is selected from the group consisting of H, alkyl, aryl, alkoxy, aryloxy and hydroxy,

R₈ is a 5-8 membered monocyclic heteroaryl or 8-11 membered bicyclic heteroaryl ring system, each of the monocyclic or bicyclic ring systems having 1-4 of the same or different heteroatoms selected from the group consisting of N, O and S wherein any of the above R₈ can be optionally substituted by one or more R_(j);

R_(j) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, arylalkyl, alkoxy, aryloxy, alkanoyl, aroyl, arylalkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylalkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl or heteroaryl; alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl; halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(j) may be further optionally substituted by one or more R_(k);

R_(k) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkoxy, aryloxy, arylalkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkoxycarbonylamino, aryloxycarbonylamino, arylalkoxycarbonylamino, arylalkoxycarbonylaminoalkyl, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, wherein R_(k) may be further optionally substituted by R₁;

R₁ is selected from the group consisting of alkyl, cycloalkyl, aryl, and benzyl;

X is O, S or N—OH;

and the pharmacurtically acceptable derivatives thereof;

with the following provisos:

when R₆ is alkyl the alkyl must be substituted with R_(f) wherein R_(f) is not hydroxy, sulfhydryl or halogen; and

when R₁ is C1alkyl then R_(b) cannot be carbamoyl, alkanoylamino, aroylamino, ureido, alkoxycarbonylamino, aryloxycarbonylamino, alkylsulfonylamino, arylsulfonylamino, amino, amidino or guanidino wherein each said R_(b) is linked to said R₁ via the nitrogen atom thereof.

Preferred compounds of the formula (Ia) are those wherein:

R_(a) is selected from the group consisting of H, alkyl and aryl;

R₁ is C1-8 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, pyranyl, thiopyranyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, or amino wherein R1 is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-8 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, C1-8 alkoxycarbonyl, aryloxycarbonyl, C1-8 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkanoylamino, aroylamino, C1-8 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, C1-8 alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-8 alkyl, C3-6 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₃ is H, C1-8 alkyl, C3-7 cycloalkyl or aryl wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C1-8 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, alkanoyl, aroyl, C1-8 alkoxycarbonyl, aryloxycarbonyl, C1-8 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkanoylamino, aroylamino, C1-8 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, C1-8 alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-8 alkyl, C3-6 cycloalkyl, aryl, arylalkyl, C1-8 alkoxy, aryloxy, arylalkoxy, aroyl, amino, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₅ is H or alkyl;

R₆ is H, C1-8 alkyl, C3-7 cycloalkyl or aryl wherein R₆ is optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of C1-8 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, arylC1-8alkoxy, heteroarylC1-8alkoxy, C1-8 alkoxycarbonyl, aryloxycarbonyl, C1-8 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkanoylamino, aroylamino, C1-8 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylC1-8 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, C1-8 alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-8 alkyl, C3-7 cycloalkyl, aryl optionally substituted by halogen, C1-3alkyl or C1-3alkoxy; heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, arylC1-8alkoxy, C1-8 alkoxycarbonyl, aryloxycarbonyl, C1-8 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkanoylamino, aroylamino, C1-8 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl or phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, C1-8 alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl and arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R_(h) is selected from the group consisting of C1-8 alkyl, aryl, C1-8 alkoxycarbonyl, aryloxycarbonyl, arylC1-8alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with a group selected from C1-8 alkyl, C3-7 cycloalkyl, aryl, arylC1-8alkyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, carboxy and cyano;

R₈ is a heteroaryl ring selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, indolizinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, indazolyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, tetrazolyl, purinyl, quinolizinyl, quinolinyl, isoquinolinyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, naphthyridinyl, pteridinyl, carbazolyl, acridinyl and phenazinyl, wherein any of the above R₈ can be optionally substituted by one or more R_(j);

R_(j) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, arylalkyl, alkoxy, aryloxy, arylalkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independantly mono or di-susbstituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkanoylamino, aroylamino, alkylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, arylalkylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, C1-8 alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-susbstituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(j) may be further optionally substituted by one or more R_(k);

R_(k) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxy, aryloxy, arylalkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independantly mono or di-susbstituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, heteroaryl selected from furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkanoylamino, aroylamino, alkylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, heteroaryl selected from furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, arylalkoxycarbonylamino, arylalkoxycarbonylaminoalkyl, C1-8 alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-susbstituted by alkyl, aryl, heterocyclyl selected from pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, wherein R_(k) may be further optionally substituted by R₁;

R₁ is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, phenyl and benzyl; and

X is O or S.

More preferred compounds of the formula (Ia) are those wherein:

Y is O or S;

R₁ is C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl pyranyl, thiopyranyl, piperazinyl and indolinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl or amino wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-5 alkyl, C3-6 cycloalkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl and pyridinyl, C1-5 alkoxy, aryloxy, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₂ is H or C1-3 alkyl;

R₃ is H, C1-5 alkyl, C3-7 cycloalkyl or aryl, wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, C1-5alkanoyl, aroyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinylor heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-5 alkyl, C3-6 cycloalkyl, aryl, arylalkyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, aroyl, amino, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₄ is H or C1-3 alkyl;

R₅ is H or C1-8 alkyl;

R₆ is H, C1-5 alkyl, C3-7 cycloalkyl or aryl wherein R₆ is optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, heteroarylC1-5alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylC1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, aryl optionally substituted by halogen, methyl or methoxy; heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl halogen, hydroxy oxo, carboxy cyano, nitro, amidino and guanidino;

R_(h) is selected from the group consisting of C1-5 alkyl, aryl, C1-5 alkoxycarbonyl, aryloxycarbonyl, arylC1-5alkoxycarbonyl carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with a group selected from C1-5 alkyl, C3-7 cycloalkyl, aryl, arylC1-5alkyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, carboxy and cyano;

R_(i) is alkoxy, aryloxy or hydroxy;

R₈ is a heteroaryl ring selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, indolizinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, indazolyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolizinyl, quinolinyl, isoquinolinyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, naphthyridinyl, pteridinyl, carbazolyl, acridinyl and phenazinyl, wherein any of the above R₈ can be optionally substituted by one or more R_(j);

R_(j) is selected from the group consisting of C1-8alkyl, C3-7cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl; arylC1-8alkyl, C1-8alkoxy, aryloxy, arylC1-8alkoxy, C1-8alkoxycarbonyl, aryloxycarbonyl, C1-8alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independantly mono or di-susbstituted by C1-8alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8alkanoylamino, aroylamino, C1-8alkylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, arylC1-8alkylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, C1-8 alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-susbstituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(j) may be further optionally substituted by one or more R_(k);

R_(k) is selected from the group consisting of C1-8 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, arylC1-8alkoxy, C1-8alkoxycarbonyl, aryloxycarbonyl, C1-8alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independantly mono or di-susbstituted by C1-8alkyl, aryl, heterocyclyl selected from pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkanoylamino, aroylamino, C1-8alkylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-8alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8alkoxycarbonylamino, aryloxycarbonylamino, arylC1-8alkoxycarbonylamino, arylalkoxycarbonylaminoC1-8alkyl, C1-8 alkylcarbamoyloxy, arylcarbamoyloxy, C1-8alkylsulfonylamino, arylsulfonylamino, C1-8alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-susbstituted by C1-8alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, wherein R_(k) may be further optionally substituted by R₁.

Even more preferred compounds of the formula (Ia) are those wherein:

Y is O;

R₁ is C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl, pyranyl and thiopyranyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, or amino wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl; C1-5 alkoxy, aryloxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl or aryl; C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy, cyano and nitro, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-5 alkyl, C3-6 cycloalkyl, aryl, C1-5 alkoxy, aryloxy, halogen, hydroxy, oxo, carboxy, and cyano;

R₂ is H or methyl;

R₃ is H, C1-5 alkyl, C3-7 cycloalkyl or phenyl, wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxy, aryloxy, aroyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-5 alkyl, C3-6 cycloalkyl, aryl, arylC1-5alkyl, C1-5 alkoxy, aryloxy, arylC1-3alkoxy, aroyl, amino, halogen, hydroxy, oxo, carboxy and cyano;

R₄ is H or methyl;

R₅ is H or C1-5 alkyl;

R₆ is H, C1-5 alkyl, C3-7 cycloalkyl, phenyl or naphthyl wherein R₆ is optionally substituted by one or more R_(f),

R_(f) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, pyridylC1-5alkoxy, thienylC1-5alkoxy, furanylC1-5alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylC1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano, Rf may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, phenyl optionally substituted by halogen, methyl or methoxy; naphthyl optionally substituted by halogen, methyl or methoxy; heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano;

R_(h) is selected from the group consisting of C1-5 alkyl, phenyl, naphthyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, arylC1-3alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with a group selected from C1-5 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, arylC1-3alkyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, carboxy and cyano;

Z is O or S;

R₈ is a heteroaryl ring selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, indolizinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, indazolyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolizinyl, quinolinyl, isoquinolinyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, naphthyridinyl, pteridinyl, carbazolyl, acridinyl and phenazinyl, wherein any of the above R₈ can be optionally substituted by one or more groups of the formula R_(j);

R_(j) is selected from the group consisting of C1-5alkyl, C3-6cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, arylC1-5alkyl, C1-5alkoxy, aryloxy, arylC1-5alkoxy, C1-5alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independantly mono or di-susbstituted by C1-5alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl, heteroaryl selected from furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5alkanoylamino, aroylamino, C1-5alkylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, arylC1-5alkylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5alkylsulfonylamino, arylsulfonylamino, C1-5alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-susbstituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, wherein R_(j) may be further optionally substituted by one or more R_(k);

R_(k) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, tetrazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, C1-3 alkoxy, aryloxy, arylC1-3alkoxy, C1-3alkoxycarbonyl, aryloxycarbonyl, C1-3alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-susbstituted by C1-3 alkyl, aryl, heterocyclyl selected from the group consisting of morpholinyland piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, and pyridinyl, C1-3alkanoylamino, aroylamino, C1-3alkylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-3alkyl, phenyl, naphthyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl and pyridinyl, C1-3alkoxycarbonylamino, aryloxycarbonylamino, arylC1-3alkoxycarbonylamino, benzyloxycarbonylaminoC1-5alkyl, C1-3 alkylcarbamoyloxy, arylcarbamoyloxy, C1-3alkylsulfonylamino, arylsulfonylamino, C1-3alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-susbstituted by C1-3alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy, cyano and nitro, wherein R_(k) may be further optionally substituted by R₁;

R₁ is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl and phenyl.

Yet even more preferred compounds of the formula (Ia) are those wherein:

R₁ is C1-5 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl, piperazinyl, pyranyl and thiopyranyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, or amino, wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-3 alkoxy, phenoxy, C1-3 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenylor heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5alkyl, phenyl or naphthyl; C1-5 alkoxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano, R_(b) may be further optionally substituted by one or more R_(e);

R_(c) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, aryl, C1-3 alkoxy, phenoxy, halogen, hydroxy, oxo, carboxy and cyano;

R₂ is H;

R₃ is C1-5 alkyl, C3-6 cycloalkyl or phenyl, wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, quinolinyl andisoquinolinyl, C1-5 alkoxy, phenoxy, aroyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, C1-5 alkanoylamino, aroylamino, C1-3 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, phenylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-3 alkyl, phenyl or heteroaryl selected the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, C1-5 alkoxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl, phenyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-5 alkyl, C5-6 cycloalkyl, phenyl, naphthyl, arylC1-3alkyl, C1-5 alkoxy, phenoxy, arylC1-3alkoxy, aroyl, amino, halogen, hydroxy, oxo, carboxy and cyano;

wherein the configuration at the stereocenter defined by R₂ and R₃ and the carbon they are attached to is L;

R₄ is H;

R₅ is H or C1-3 alkyl;

R₆ is H, C1-5 alkyl, C3-6 cycloalkyl or phenyl, wherein R₆ is optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxy, aryloxy, arylC1-3alkoxy, pyridylC1-5alkoxy, thienylC1-5alkoxy, furanylC1-5alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenylor heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, C1-5 alkanoylamino, aroylamino, C1-3 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylC1-3alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl or phenyl; C1-5 alkoxycarbonylamino, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, halogen, hydroxy, oxo, carboxy and cyano, Rf may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, phenyl optionally substituted by halogen, methyl or methoxy; heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, pyrimidinyl, pyrazinyl and indolyl, C1-5 alkoxy, aryloxy, arylC1-3alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or aryl; C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl or aryl; C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or aryl; halogen hydroxy, oxo, carboxy and cyano;

R_(h) is selected from the group consisting of C1-5 alkyl, phenyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, arylC1-3alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with C1-5 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, arylC1-3alkyl, halogen, hydroxy, carboxy and cyano;

wherein Z is O;

R₈ is a heteroaryl ring selected from the group consisting of oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, wherein any of the above R₈ can be optionally substituted by one or more R_(j);

R_(j) is selected from the group consisting of C1-5 alkyl, C5-6 cycloalkyl, phenyl, naphthyl, pyrrolidinyl, piperidinyl, morpholinyl, piperazinyl, furanyl, thienyl, pyrrolyl, tetrazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, arylC1-3alkyl, C1-3alkoxy, aryloxy, arylC1-3alkoxy, C1-3alkoxycarbonyl, aryloxycarbonyl, C1-3alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independantly mono or di-susbstituted by C1-3alkyl, phenyl, naphthyl, piperidinyl, furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl; C1-3alkanoylamino, aroylamino, C1-3alkylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, arylC1-3alkylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-3 alkyl, phenyl, naphthyl, piperidinyl, morpholinyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl; C1-3 alkoxycarbonylamino, aryloxycarbonylamino, C1-3 alkylcarbamoyloxy, arylcarbamoyloxy, C1-3alkylsulfonylamino, arylsulfonylamino, C1-3alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-susbstituted by C1-3 alkyl, phenyl, naphthyl, piperidinyl, furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyland isoquinolinyl; halogen, hydroxy, oxo, carboxy, cyano and nitro, R_(j) may be further optionally substituted by one or more R_(k);

R_(k) is selected from the group consisting of methyl, C5-6 cycloalkyl, phenyl, pyrrolidinyl, piperidinyl, morpholinyl, piperazinyl, furanyl, thienyl, pyrrolyl, tetrazolyl, pyridinyl pyrimidinyl, C1-3 alkoxy, phenoxy benzyloxy, methoxycarbonyl, acetyloxy, benzoyloxy, carbamoyl wherein the nitrogen atom may be independantly mono or di-susbstituted by C1-3 alkyl, phenyl, furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl or pyridinyl; acetylamino, benzoylamino, methylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by methyl, phenyl, furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl or pyridinyl; arylC1-3alkoxycarbonylamino, benzyloxycarbonylaminoC1-5alkyl, methylcarbamoyloxy, amino wherein the nitrogen atom may be independently mono or di-susbstituted by C1-3alkyl, phenyl, naphthyl, pyrrolidinyl, piperidinyl, furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, pyrimidinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl or isoquinolinyl, halogen, hydroxy, oxo, carboxy, cyano and nitro, wherein R_(k) may be further optionally substituted by R₁;

R₁ is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl and phenyl.

Still yet even more preferred compounds of the formula (Ia) are those wherein:

R₁ is C1-3 alkyl, C5-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl, piperazinyl, pyranyl and thiopyranyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, or amino, wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, phenyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl, C1-3 alkoxy, C1-3 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl, phenylor heteroaryl selected from the group consisting of pyrrolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl and benzthiazolyl; C1-5 alkanoylamino, aroylamino, C1-3 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-3alkyl or phenyl; C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3alkyl, phenyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinylor heteroaryl selected from the group consisting of pyrrolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyl and isoquinolinyl; halogen, hydroxy, oxo, carboxy and cyano, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, C1-3 alkoxy, halogen and hydroxy;

R₃ is C1-5 alkyl, C5-6 cycloalkyl or phenyl wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, 4-piperidinyl, 4-morpholinyl, piperazinyl, furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, C1-5 alkoxy, phenoxy, aroyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or phenyl; C1-5 alkanoylamino, C1-3 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-3 alkyl or phenyl; C1-5 alkoxycarbonylamino, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl; halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-5 alkyl, C5-6 cycloalkyl, phenyl, benzyl, C1-5 alkoxy, phenoxy, benzyloxy, aroyl, halogen, hydroxy, oxo, carboxy and cyano;

R₆ is H, C1-5 alkyl or phenyl wherein R₆ is optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, C1-3 alkoxy, benzyloxy, pyridyl, C1-3alkoxy, thienylC1-3alkoxy, furanylC1-3alkoxy, C1-3 alkoxycarbonyl, phenoxyoxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl; C1-5 alkanoylamino, aroylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl or phenyl; C1-3 alkoxycarbonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or phenyl; halogen, hydroxy, oxo, carboxy and cyano, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-3 alkyl, phenyl optionally substituted by halogen, methyl or methoxy; heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl and pyridinyl, C1-3 alkoxy, aryloxy, benzyloxy, C1-5 alkoxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or phenyl; C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl or phenyl; C1-5 alkoxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-3 alkylsulfonylamino, arylsulfonylamino, C1-3 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl; halogen, hydroxy, oxo, carboxy and cyano;

R_(h) is selected from the group consisting of C1-3 alkyl, phenyl, C1-3 alkoxycarbonyl, phenoxyoxycarbonyl, benzyloxy, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with C1-5 alkyl, phenyl, benzyl, halogen, hydroxy, carboxy and cyano;

R₈ is a heteroaryl ring selected from the group consisting of oxazolyl, thiazolyl, imidazolyl, pyrazolyl, pyridyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, quinolinyland isoquinolinyl, wherein any of the above R8 can be optionally substituted by one or more R_(j);

R_(j) is selected from the group consisting of C1-5 alkyl, C5-6 cycloalkyl, phenyl, naphthyl, pyrrolidinyl, piperidinyl, morpholinyl, piperazinyl, furanyl, thienyl, pyrrolyl, tetrazolyl, pyridinyl, pyrimidinyl, benzyl, C1-3alkoxy, phenoxy, benzyloxy, C1-3alkoxycarbonyl, acetyloxy, benzoyloxy, carbamoyl wherein the nitrogen atom may be independantly mono or di-susbstituted by methyl, phenyl, furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl and pyridinyl; acetylamino, benzoylamino, methylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, benzylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by methyl, phenyl, thiazolyl, imidazolyl and pyridinyl; C1-3 alkoxycarbonylamino, C1-3 alkylcarbamoyloxy, arylcarbamoyloxy, C1-3alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-susbstituted by methyl, phenyl, furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl and pyridinyl; halogen, hydroxy, carboxy, cyano and nitro, R_(j) may be further optionally substituted by one or more R_(k);

R_(k) is selected from the group consisting of methyl C5-6 cycloalkyl, phenyl, pyrrolidinyl, piperidinyl, morpholinyl, piperazinyl, furanyl, thienyl, pyrrolyl, pyridinyl, C1-3 alkoxy, phenoxy, benzyloxy, methoxycarbonyl, acetyloxy, benzoyloxy, carbamoyl wherein the nitrogen atom may be independantly mono or di-susbstituted by methyl, phenyl, furanyl, thienyl; acetylamino, benzoylamino, methylthio wherein the sulfur atom may be oxidised to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by methyl, phenyl, furanyl, thienyl, pyrrolyl, oxazolyl and thiazolyl, benzyloxycarbonylamino, benzyloxycarbonylaminoC1-5alkyl, amino wherein the nitrogen atom may be independently mono or di-susbstituted by C1-3alkyl, phenyl, furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl and pyridinyl, halogen, hydroxy, carboxy, cyano and nitro, wherein R_(k) may be further optionally substituted by R₁;

R₁ is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl and phenyl.

Even much more preferred compounds of the formula (Ia) are those wherein:

R₁ is C5-6 cycloalkyl, phenyl, naphthyl, piperidinyl, morpholinyl, piperazinyl, furanyl, thienyl, pyrrolyl, pyranyl, thiopyranyl or amino wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, phenyl, furanyl, thienyl, pyrrolyl, imidazolyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, C1-3 alkoxy, C1-3 alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl; C1-5 alkanoylamino, aroylamino, ureido wherein either nitrogen atom may be independently substituted by C1-3alkyl or phenyl; C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3alkyl or phenyl; halogen, hydroxy, oxo, carboxy and cyano, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-3 alkyl, C1-3 alkoxy, halogen and hydroxy;

R_(d) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, 4-piperidinyl, furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, C1-3alkoxy, C1-5alkoxycarbonyl, C1-5alkanoyloxy, benzoyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3alkyl or phenyl; C1-5alkanoylamino, C1-3 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, C1-3alkoxycarbonylamino, C1-3alkylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl, halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-3 alkyl, phenyl, benzyl, C1-3 alkoxy, phenoxy, benzyloxy, benzoyl, halogen, hydroxy, oxo, carboxy and cyano;

R₅ is H or methyl;

R₆ is C1-5 alkyl or phenyl, wherein R₆ is optionally substituted by one or more groups of the formula R_(f);

R_(f) is selected from the group consisting of methyl, C3-6 cycloalkyl, phenyl, naphthyl, furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, C1-3 alkoxy, benzyloxy, C1-5 alkanoylamino, aroylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, C1-3 alkoxycarbonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or phenyl; halogen, hydroxy, oxo, carboxy and cyano, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-3 alkyl, phenyl optionally substituted by halogen or methyl; C1-3 alkoxy, aryloxy, benzyloxy, C1-3 alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl; C1-5 alkanoylamino, aroylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl; halogen, hydroxy, oxo, carboxy and cyano;

R_(h) is selected from the group consisting of C1-3 alkyl, phenyl, C1-3 alkoxycarbonyl, benzyloxy and carboxy;

R₈ is a heteroaryl ring selected from the group consisting of oxazolyl, thiazolyl, imidazolyl, pyrazolyl, pyridyl, benzimidazolyl, benzthiazolyland benzoxazolyl, wherein any of the above R₈ can be optionally substituted by one or more R_(j);

R_(j) is selected from the group consisting of C1-5 alkyl, cyclohexyl, phenyl, piperidinyl, furanyl, thienyl, pyridinyl, benzyl, methoxy, phenoxy, benzyloxy, methoxycarbonyl, acetyloxy, benzoyloxy, carbamoyl wherein the nitrogen atom may be independantly mono or di-susbstituted by methyl, phenyl, furanyl, thienyl; acetylamino, benzoylamino, ureido wherein either nitrogen atom may be independently substituted by methyl or phenyl; methoxycarbonylamino, C1-3 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-susbstituted by methyl, phenyl, furanyl or thienyl; halogen, hydroxy, carboxy and cyano, R_(j) may be further optionally substituted by one or more R_(k);

R_(k) is selected from the group consisting of methyl, C5-6 cycloalkyl, phenyl, piperidinyl, piperazinyl, furanyl, thienyl, C1-3 alkoxy, phenoxy, benzyloxy, methoxycarbonyl, acetyloxy, benzoyloxy, carbamoyl wherein the nitrogen atom may be independantly mono or di-susbstituted by methyl or phenyl; acetylamino, benzoylamino, ureido wherein either nitrogen atom may be independently substituted by methyl or phenyl; benzyloxycarbonylamino, benzyloxycarbonylamino C1-5alkyl, amino wherein the nitrogen atom may be independently mono or di-susbstituted by C1-3 alkyl, phenyl, furanyl, or thienyl; halogen, hydroxy, carboxy, cyano and nitro wherein R_(k) may be further optionally substituted by R₁;

R₁ is selected from the group consisting of methyl, C3-6 cycloalkyl and phenyl.

Yet even more preferred compounds of the formula (Ia) are those wherein:

A is —C(O)— or —SO₂—;

R₁ is cyclohexyl, phenyl, naphthyl, piperidinyl morpholinyl, piperazinyl pyranyl, thiopyranyl or amino, wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, phenyl, furanyl, thienyl, pyrrolyl, imidazolyl, indolyl, benzofuranyl benzothienyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, C1-3 alkoxy, C1-3 alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl; C1-5 alkanoylamino, aroylamino, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl; halogen, hydroxy, oxo, carboxy and cyano, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-3 alkoxy, halogen and hydroxy;

R₃ is C1-5 alkyl or C5-6 cycloalkyl, wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of methyl, C3-6 cycloalkyl, phenyl, thienyl, imidazolyl, pyridinyl, indolyl, C1-4 alkoxy, C1-5 alkanoylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of methyl, phenyl, benzyl, methoxy, phenoxy, benzyloxy, benzoyl, halogen and hydroxy;

R_(f) is selected from the group consisting of C3-6 cycloalkyl, phenyl, naphthyl, thienyl, imidazolyl, pyridinyl, indolyl, methoxy, benzyloxy, C1-3 alkanoylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, methoxycarbonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl; halogen, hydroxy, carboxy and cyano, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of methyl, phenyl optionally substituted by halogen or methyl; methoxy, phenoxy, benzyloxy, methoxycarbonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl; halogen, hydroxy and carboxy;

R₈ is a heteroaryl ring selected from the group consisting of oxazolyl, thiazolyl, imidazolyl, pyridyl, benzthiazolyl and benzoxazolyl, wherein any of the above R₈ can be optionally substituted by one or more R_(j);

R_(j) is selected from the group consisting of C1-5 alkyl, phenyl, furanyl, thienyl, piperidinyl, pyridinyl, benzyl, methoxy, methoxycarbonyl, acetyloxy, benzoyloxy, carbamoyl wherein the nitrogen atom may be independantly mono or di-susbstituted by methyl or phenyl; acetylamino, benzoylamino, ureido wherein either nitrogen atom may be independently substituted by methyl or phenyl; methoxycarbonylamino, amino wherein the nitrogen atom may be independently mono or di-susbstituted by methyl, phenyl; halogen, hydroxy, carboxy and cyano, R_(j) may be further optionally substituted by one or more R_(k); and

R_(k) is selected from the group consisting of methyl, C5-6 cycloalkyl, phenyl, piperidinyl, methoxy, phenoxy, benzyloxy, methoxycarbonyl, carbamoyl wherein the nitrogen atom may be independantly mono or di-susbstituted by methyl or phenyl; ureido wherein either nitrogen atom may be independently substituted by methyl or phenyl; benzyloxycarbonylamino, benzyloxycarbonylaminoC1-5alkyl, amino wherein the nitrogen atom may be independently mono or di-susbstituted by C1-3alkyl, phenyl, furanyl and thienyl; halogen, hydroxy, carboxy, cyano and nitro, wherein R_(k) may be further optionally substituted by R₁;

R₁ is selected from the group consisting of methyl and phenyl.

Penultimately preferred compounds of the formula (Ia) are those wherein:

R₁ is cyclohexyl, phenyl, naphthyl, piperidinyl, morpholinyl, piperazinyl, pyranyl or thiopyranyl, wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of, pyrrolyl, imidazolyl, indolyl, benzimidazolyl, methoxy, methoxycarbonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl; halogen, hydroxy and carboxy, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of methoxy, halogen and hydroxy;

R_(d) is selected from the group consisting of methyl, C3-6 cycloalkyl, phenyl, C1-4 alkoxy, C1-3 alkanoylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of methyl, phenyl, methoxy, halogen and hydroxy;

R₅ is H;

R_(f) is selected from the group consisting of C5-6 cycloalkyl, phenyl, naphthyl, thienyl, indolyl, methoxy, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, methoxycarbonylamino, halogen, hydroxy, carboxy and cyano, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of methyl, phenyl optionally substituted by halogen; methoxy, phenoxy, benzyloxy, methoxycarbonyl, halogen, hydroxy and carboxy;

R₈ is a heteroaryl ring selected from the group consisting of oxazolyl, thiazolyl, pyridyl, benzthiazolyl and benzoxazolyl, wherein any of the above R₈ can be optionally substituted by one or more R_(j);

R_(j) is selected from the group consisting of C1-5 alkyl, phenyl, piperidinyl, pyridinyl, benzyl, methoxy, methoxycarbonyl, acetyloxy, benzoyloxy, carbamoyl wherein the nitrogen atom may be independantly mono or di-susbstituted by methyl or phenyl; methoxycarbonylamino halogen, hydroxy and carboxy, R_(j) may be further optionally substituted by one or more R_(k);

R_(k) is selected from the group consisting of methyl, C5-6 cycloalkyl, phenyl, piperidinyl, methoxy, methoxycarbonyl, carbamoyl wherein the nitrogen atom may be independently mono or di-susbstituted by methyl or phenyl; benzyloxycarbonylamino, amino wherein the nitrogen atom may be independently mono or di-susbstituted by methyl or phenyl; halogen, hydroxy and carboxy.

Ultimately preferred compounds of the formula (Ia) are those wherein:

R₁ is phenyl or 4-morpholinyl, wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of benzimidazolyl, methoxy and dimethylamino, R_(b) may be further optionally substituted by a halogen atom;

R₃ is C1-5 alkyl wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C3-6 cycloalkyl and phenyl, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of methyl and halogen;

R₆ is C1-5 alkyl optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of C5-6 cycloalkyl, phenyl, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone and halogen, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of methyl, methoxy, methoxycarbonyl, halogen and hydroxy;

R₈ is a heteroaryl ring selected from the group consisting of oxazolyl, pyridyl, benzthiazolyl and benzoxazolyl, wherein any of the above R₈ can be optionally substituted by one or more R_(j);

R_(j) is selected from the group consisting of C1-5 alkyl, phenyl, pyridinyl, piperidinyl, methoxycarbonyl, carbamoyl wherein the nitrogen atom may be independantly mono or disubstituted by methyl or phenyl; methoxycarbonylamino and halogen, R_(j) may be further optionally substituted by one or more R_(k);

R_(k) is selected from the group consisting of methyl, C5-6 cycloalkyl, phenyl, methoxycarbonyl, carbamoyl, benzyloxycarbonylamino and halogen.

The invention also provides novel compounds of the formula (II):

wherein:

A is —C(Y)—or —SO₂—

Y is O, S or NR_(a) wherein R_(a) is selected from the group consisting of H, alkyl, aryl, alkoxy, aryloxy, alkylamino and arylamino;

R₁ is alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl or amino wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkoxy, aryloxy, alkanoyl, aroyl, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino; R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, arylalkyl, alkoxy, aryloxy, arylalkoxy, alkanoyl, aroyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₂ is H or alkyl;

R₃ is 1L, alkyl, cycloalkyl, aryl, heterocyclyl or heteroaryl, wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkoxy, aryloxy, arylalkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyl, aroyl alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of alkyl, cycloalkyl, aryl, arylalkyl, alkoxy, aryloxy, arylalkoxy, alkanoyl, aroyl, amino, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₄ is H or alkyl;

R₅ is H or alkyl;

R₆ is H, alkyl, cycloalkyl, aryl, heterocyclyl, aryl, heteroaryl or cyano, wherein R₆ is optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkoxy, aryloxy, arylalkoxy, alkanoyl, aroyl, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, aroyloxy, heteroarylalkoxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylcarbamoyl, arylcarbamoyl, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylalkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of alkyl, cycloalkyl, aryl optionally substituted by one or more groups selected from halogen, methyl or methoxy, heterocyclyl, heteroaryl, alkoxy, aryloxy, arylalkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylcarbamoyl, arylcarbamoyl, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

or R₅ together with R₆ form a 3 to 6 membered carbocyclic ring, the carbocyclic ring being optionally substituted with one or more R_(h);

R_(h) is selected from the group consisting of alkyl, aryl, alkoxycarbonyl, aryloxycarbonyl, arylalkoxycarbonyl, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with a group selected from alkyl, cycloalkyl, aryl arylalkyl, heterocyclyl, heteroaryl, halogen, hydroxy, carboxy and cyano;

X is O, S or N—OH;

with the proviso that when Y is O and R₆ is arylalkyl or heteroarylalkyl then R₁ cannot be alkyl, cycloalkyl aryl, heteroaryl, cycloalkyl-alkyl, aryl-alkyl or aryl-cycloalkyl.

Preferred compounds of the formula (II) are those wherein:

Y is O, S or NR_(a) wherein R_(a) is H, alkyl or aryl;

R₁ is C1-8alkyl, C3-7cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl thiomorpholinyl, piperazinyl, indolinyl, pyranyl and thiopyranyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl, phenoxazinyl, and amino wherein R1 is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-8 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl or phenoxazinyl, C1-8 alkoxy, aryloxy, C1-8 alkoxycarbonyl, aryloxycarbonyl, C1-8 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkanoylamino, aroylamino, C1-8 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl or phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, pyrazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino, guanidino; R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-8 alkyl, C3-6 cycloalkyl, aryl, C1-8 alkoxy, aryloxy, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₃ is H, C1-8 alkyl, C3-7 cycloalkyl, aryl wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C1-8 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, alkanoyl, aroyl, C1-8 alkoxycarbonyl, aryloxycarbonyl, C1-8 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkanoylamino, aroylamino, C1-8 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino, guanidino, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-8 alkyl, C3-6 cycloalkyl, aryl, arylalkyl, C1-8 alkoxy, aryloxy, arylalkoxy, aroyl, amino, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino,

R₆ is H, C1-8 alkyl, C3-7 cycloalkyl, aryl or cyano, wherein R₆ is optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of C1-8 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, arylC1-8alkoxy, heteroarylC1-8alkoxy, C1-8 alkoxycarbonyl, aryloxycarbonyl, C1-8 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkanoylamino, aroylamino, C1-8 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylC1-8 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-8 alkyl, C3-7 cycloalkyl, aryl optionally substituted by one or more groups selected from halogen, methyl or methoxy, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, arylC1-8alkoxy, C1-8 alkoxycarbonyl, aryloxycarbonyl, C1-8 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkanoylamino, aroylamino, C1-8 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino, and guanidino;

R_(h) is selected from the group consisting of C1-8 alkyl, aryl, C1-8 alkoxycarbonyl, aryloxycarbonyl, arylC1-8alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with a group selected from C1-8 alkyl, C3-7 cycloalkyl, aryl, arylC1-8alkyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, carboxy, and cyano; and

X is O or S.

More preferred compounds of the formula (II) are those wherein:

Y is O or S;

R₁ is C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl, indolinyl, pyranyl and thiopyranyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl or amino; wherein R1 is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-5 alkyl, C3-6 cycloalkyl, aryl, C1-5 alkoxy, aryloxy, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₂ is H or C1-3 alkyl;

R₃ is H, C1-5 alkyl, C3-7 cycloalkyl, aryl wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, C1-5alkanoyl, aroyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-5 alkyl, C3-6 cycloalkyl, aryl, arylalkyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, aroyl, amino, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₄ is H or C1-3 alkyl

R₅ is H or C1-8 alkyl

R₆ is H, C1-5 alkyl, C3-7 cycloalkyl, aryl or cyano, wherein R₆ is optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, heteroarylC1-5alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylC1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, oxo, carboxy cyano, nitro, amidino and guanidino, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, aryl optionally substituted by one or more groups selected from halogen, methyl or methoxy, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R_(h) is selected from the group consisting of C1-5 alkyl, aryl, C1-5 alkoxycarbonyl, aryloxycarbonyl, arylC1-5alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with a group selected from C1-5 alkyl, C3-7 cycloalkyl, aryl, arylC1-5alkyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, carboxy and cyano.

Even more preferred compounds of the formula (II) are those wherein:

Y is O;

R₁ is C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl, pyranyl and thiopyranyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl; or amino wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxy, aryloxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl or aryl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy, cyano and nitro, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-5 alkyl, C3-6 cycloalkyl, aryl, C1-5 alkoxy, aryloxy, halogen, hydroxy, oxo, carboxy and cyano;

R₂ is H or methyl;

R₃ is H, C1-5 alkyl, C3-7 cycloalkyl or phenyl wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxy, aryloxy, aroyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-5 alkyl, C3-6 cycloalkyl, aryl, arylC1-5alkyl, C1-5 alkoxy, aryloxy, arylC1-3alkoxy, aroyl, amino, halogen, hydroxy, oxo, carboxy and cyano;

R₄ is H or methyl;

R₅ is H or C1-5 alkyl;

R₆ is H, C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl or cyano, wherein R₆ is optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, heteroarylC1-5alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylC1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, phenyl optionally substituted by one or more groups selected from halogen, methyl or methoxy, naphthyl optionally substituted by one or more groups selected from halogen, methyl or methoxy, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano;

R_(h) is selected from the group consisting of C1-5 alkyl, phenyl, naphthyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, arylC1-3alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with a group selected from C1-5 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, arylC1-3alkyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, carboxy and cyano; and

X is O.

Yet even more preferred compounds of the formula (II) are those wherein:

Y is O;

R₁ is C1-5 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl, piperazinyl, pyranyl and thiopyranyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl or amino, wherein R₁ is optionally substituted by one or more R_(h);

R_(b) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-3 alkoxy, phenoxy, C1-3 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenylor heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5alkyl, phenyl or naphthyl; C1-5 alkoxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, aryl, C1-3 alkoxy, phenoxy, halogen, hydroxy, oxo, carboxy and cyano;

R₂ is H;

R₃ is C1-5 alkyl, C3-6 cycloalkyl or phenyl, wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, quinolinyl and isoquinolinyl, C1-5 alkoxy, phenoxy, aroyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, C1-5 alkanoylamino, aroylamino, C1-3 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, phenylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-3 alkyl, phenyl or heteroaryl selected the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, C1-5 alkoxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl, phenyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-5 alkyl, C5-6 cycloalkyl, phenyl, naphthyl, arylC1-3alkyl, C1-5 alkoxy, phenoxy, arylC1-3alkoxy, aroyl, amino, halogen, hydroxy, oxo, carboxy and cyano;

R₄ is H,

R₆ is H, C1-5 alkyl, C3-6 cycloalkyl, phenyl or cyano, wherein R₆ is optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxy, aryloxy, arylC1-3 alkoxy, heteroarylC1-3alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-3 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenylor heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, C1-5 alkanoylamino, aroylamino, C1-3 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylC1-3alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl or phenyl, C1-5 alkoxycarbonylamino, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by Cl1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, halogen, hydroxy, oxo, carboxy and cyano, Rf may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-3alkyl, C5-6 cycloalkyl, phenyl optionally substituted by one or more groups selected from halogen or methyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, pyrimidinyl, pyrazinyl and indolyl, C1-5 alkoxy, aryloxy, arylC1-3alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or aryl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl or aryl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or aryl, halogen, hydroxy, oxo, carboxy and cyano;

R_(h) is selected from the group consisting of C1-5 alkyl, phenyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, arylC1-3alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with C1-5 alkyl, C3-6 cycloalkyl, phenyl, naphthyl or arylC1-3alkyl; halogen, hydroxy, carboxy and cyano.

Still yet even more preferred compounds of the formula (II) are those wherein:

R₁ is C1-3 alkyl, C5-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl, piperazinyl, pyranyl and thiopyranyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl or amino, wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, phenyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-3 alkoxy, C1-3 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl, phenylor heteroaryl selected from the group consisting of pyrrolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl and benzthiazolyl C1-5 alkanoylamino, aroylamino, C1-3 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-3alkyl or phenyl, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3alkyl, phenyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of pyrrolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano, R_(b) may be further optionally substituted by one or more R_(c);

R₃ is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, C1-3 alkoxy, halogen and hydroxy;

R₃ is C1-5 alkyl, C5-6 cycloalkyl or phenyl wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl 4-piperidinyl, 4-morpholinyl, piperazinyl, furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, C1-5 alkoxy, phenoxy, aroyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or phenyl, C1-5 alkanoylamino, C1-3 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-3 alkyl or phenyl, C1-5 alkoxycarbonylamino, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl, halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-5 alkyl, C5-6 cycloalkyl, phenyl, benzyl, C1-5 alkoxy, phenoxy, benzyloxy, aroyl, halogen, hydroxy, oxo, carboxy and cyano;

R₅ is H or C1-3alkyl;

R₆ is H, C1-5 alkyl, phenyl or cyano, wherein R₆ is optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, C1-3 alkoxy, benzyloxy, pyridylC1-3alkoxy, thienylC1-3alkoxy, furanylC1-3alkoxy, C1-3 alkoxycarbonyl, phenoxyoxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl, C1-5 alkanoylamino, aroylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl or phenyl, C1-3 alkoxycarbonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or phenyl, halogen, hydroxy, oxo, carboxy and cyano, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-3 alkyl, phenyl optionally substituted by one or more groups selected from the group consisting of halogen and methyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl and pyridinyl, C1-3 alkoxy, aryloxy, benzyloxy, C1-5 alkoxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or phenyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl or phenyl, C1-5 alkoxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-3 alkylsulfonylamino, arylsulfonylamino, C1-3 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl, halogen, hydroxy, oxo, carboxy and cyano;

R_(h) is selected from the group consisting of C1-3 alkyl, phenyl, C1-3 alkoxycarbonyl, phenoxyoxycarbonyl, benzyloxy, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with a group selected from the group consisting of C1-5 alkyl, phenyl and benzyl, halogen, hydroxy, carboxy and cyano.

Even more preferred compounds of the formula (II) are those wherein:

R₁ is C5-6 cycloalkyl, phenyl, naphthyl, piperidinyl, morpholinyl, piperazinyl, pyranyl, thiopyranyl, furanyl, thienyl, pyrrolyl or amino, wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, phenyl, furanyl, thienyl, pyrrolyl, imidazolyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, C1-3 alkoxy, C1-3 alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl; C1-5 alkanoylamino, aroylamino, ureido wherein either nitrogen atom may be independently substituted by C1-3alkyl or phenyl; C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3alkyl or phenyl, halogen, hydroxy oxo, carboxy and cyano, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-3alkyl, C1-3alkoxy, halogen and hydroxy;

R₃ is C1-5 alkyl, C5-6 cycloalkyl or phenyl, wherein R₃ is optionally substituted by one or more groups of the formula R_(d);

R_(d) is selected from the group consisting of C1-3 alkyl C3-6 cycloalkyl, phenyl, naphthyl, 4-piperidinyl, furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, C1-3 alkoxy, C1-5 alkoxycarbonyl, C1-5 alkanoyloxy, benzoyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl, C1-5 alkanoylamino, C1-3 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, C1-3 alkoxycarbonylamino, C1-3 alkylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl, halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-3 alkyl, phenyl, benzyl, C1-3 alkoxy, phenoxy, benzyloxy, benzoyl, halogen, hydroxy, oxo, carboxy and cyano;

wherein the configuration at the stereocenter defined by R₂ and R₃ and the carbon they are attached to is defined as L;

R₅ is H or methyl;

R₆ is C1-5 alkyl phenyl or cyano wherein R₆ is optionally substituted by one or more groups of the formula R_(f);

R_(f) is selected from the group consisting of methyl, C3-6 cycloalkyl, phenyl, naphthyl, furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, C1-3 alkoxy, benzyloxy, pyridylC1-3alkoxy, thienylC1-3alkoxy, furanylC1-3alkoxy, C1-5 alkanoylamino, aroylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, C1-3 alkoxycarbonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or phenyl, halogen, hydroxy, oxo, carboxy and cyano, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-3 alkyl, phenyl optionally substituted by one or more groups selected from halogen or methyl, C1-3 alkoxy, aryloxy, benzyloxy, C1-3 alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl, C1-5 alkanoylamino, aroylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl, halogen, hydroxy, oxo, carboxy and cyano;

R_(h) is selected from the group consisting of C1-3 alkyl, phenyl, C1-3 alkoxycarbonyl, benzyloxy and carboxy.

Much more preferred compounds of formula (II) are those wherein:

R₁ is cyclohexyl, phenyl, naphthyl, piperidinyl, morpholinyl, piperazinyl, pyranyl, thiopyranyl or amino wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, phenyl, furanyl, thienyl, pyrrolyl, imidazolyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, C1-3 alkoxy, C1-3 alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl, halogen, hydroxy, oxo, carboxy and cyano, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-3 alkoxy, halogen and hydroxy,

R₃ is C1-5 alkyl or C5-6 cycloalkyl wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of methyl, C3-6 cycloalkyl, phenyl, naphthyl, thienyl, imidazolyl, pyridinyl, indolyl, C1-4 alkoxy, C1-5 alkanoylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(c) is selected from the group consisting of methyl, phenyl, benzyl, methoxy, phenoxy, benzyloxy, benzoyl, halogen and hydroxy;

R₆ is C1-5 alkyl or phenyl, wherein R₆ is optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of C3-6 cycloalkyl, phenyl, naphthyl, thienyl, imidazolyl, pyridinyl, indolyl, methoxy, benzyloxy, C1-3 alkanoylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, methoxycarbonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl, halogen, hydroxy, carboxy and cyano, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of methyl, phenyl optionally substituted by one or more groups selected from halogen or methyl, methoxy, phenoxy, benzyloxy, methoxycarbonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl, halogen, hydroxy and carboxy;

R_(h) is selected from the group consisting of vinyl phenyl, methoxycarbonyl, benzyloxycarbonyl and carboxy;

Penultimately preferred compounds of the formula (II) are those wherein:

R₁ is cyclohexyl, phenyl, naphthyl, piperidinyl, morpholinyl, piperazinyl, pyranyl or thiopyranyl, wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of pyrrolyl, imidazolyl, indolyl, benzimidazolyl, methoxy, methoxycarbonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl, halogen, hydroxy and carboxy, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of methoxy, halogen and hydroxy;

R_(d) is selected from the group consisting of methyl, C3-6 cycloalkyl, phenyl, naphthyl, C1-4 alkoxy, C1-3 alkanoylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of methyl, phenyl, methoxy, halogen and hydroxy;

R₅ is H;

R_(f) is selected from the group consisting of C5-6 cycloalkyl, phenyl, naphthyl, thienyl, indolyl, methoxy, benzyloxy, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, methoxycarbonylamino, halogen, hydroxy, carboxy and cyano, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of methyl, phenyl optionally substituted by halogen, methoxy, phenoxy, benzyloxy, methoxycarbonyl, halogen, hydroxy and carboxy;

R_(h) is vinyl or phenyl.

Ultimately preferred compounds of formula (II) are those wherein:

R₁ is phenyl, naphthyl or 4-morpholinyl wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of benzimidazolyl, methoxy and dimethylamino R_(b) may be further optionally substituted by R_(c) wherein R_(c) is a halogen atom;

R₃ is C1-5 alkyl wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C3-6 cycloalkyl, phenyl or naphthyl R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of methyl and halogen,

R_(f) is selected from the group consisting of C5-6 cycloalkyl, phenyl, naphthyl, indolyl, benzyloxy, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, halogen and carboxy, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of methyl, methoxy, methoxycarbonyl, halogen and hydroxy.

In another embodiment of the invention, there are provided compounds of the formula (IIa):

wherein:

A is —C(Y)—or —SO₂—

Y is O, S or NR_(a) wherein R_(a) is selected from the group consisting of H, alkyl, aryl, alkoxy, aryloxy, alkylamino and arylamino;

R₁ is alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl or amino wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkoxy, aryloxy, alkanoyl, aroyl, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino; R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, arylalkyl, alkoxy, aryloxy, arylalkoxy, alkanoyl, aroyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₂ is H or alkyl;

R₃ is H, C2-8alkyl, cycloalkyl, aryl, heterocyclyl or heteroaryl, wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkoxy, aryloxy, arylalkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyl, aroyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of alkyl, cycloalkyl, aryl, arylalkyl, alkoxy, aryloxy, arylalkoxy, alkanoyl, aroyl, amino, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₄ is H or alkyl;

R₅ is H or alkyl;

R₆ is H, alkyl, cycloalkyl, aryl, heterocyclyl, aryl, heteroaryl or cyano, wherein R₆ is optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkoxy, aryloxy, arylalkoxy, alkanoyl, aroyl, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, aroyloxy, heteroarylalkoxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylcarbamoyl, arylcarbamoyl, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylalkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of alkyl, cycloalkyl, aryl optionally substituted by one or more groups selected from halogen, methyl or methoxy, heterocyclyl, heteroaryl, alkoxy, aryloxy, arylalkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylcarbamoyl, arylcarbamoyl, alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

or R₅ and R₆ together with the carbon they are attached form a carbocyclic ring of 3 to 6 carbon atoms, the carbocyclic ring being optionally substituted with one or more R_(h);

R_(h) is selected from the group consisting of alkyl, aryl, alkoxycarbonyl, aryloxycarbonyl, arylalkoxycarbonyl, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with a group selected from alkyl, cycloalkyl, aryl, arylalkyl, heterocyclyl, heteroaryl, halogen, hydroxy, carboxy and cyano;

X is O, S or N—OH;

and the pharmaceutically acceptable salts, esters or tautomers thereof;

with the following provisos:

when Y is O and R₆ is arylalkyl or heteroarylalkyl then R₁ cannot be alkyl, cycloalkyl, aryl, heteroaryl, cycloalkyl-alkyl, aryl-alkyl or aryl-cycloalkyl;

when R₅ is H then R₆ cannot be H; and

when R₁ is C1alkyl then R_(b) cannot be carbamoyl, alkanoylamino, aroylamino, ureido, alkoxycarbonylamino, aryloxycarbonylamino, alkylsulfonylamino, arylsulfonylamino, amino, amidino or guanidino wherein each said R_(b) is linked to said R₁ via the nitrogen atom thereof.

Preferred compounds of the formula (IIa) are those wherein:

Y is O, S or NR_(a) wherein R_(a) is H, alkyl or aryl;

R₁ is C1-8alkyl, C3-7cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl, indolinyl, pyranyl and thiopyranyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl, phenoxazinyl, and amino wherein R1 is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-8 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl or phenoxazinyl, C1-8 alkoxy, aryloxy, C1-8 alkoxycarbonyl, aryloxycarbonyl, C1-8 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkanoylamino, aroylamino, C1-8 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl or phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, pyrazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino, guanidino; R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-8 alkyl, C3-6 cycloalkyl, aryl, C1-8 alkoxy, aryloxy, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₃ is H, C2-8 alkyl, C3-7 cycloalkyl, aryl wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C1-8 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, alkanoyl, aroyl, C1-8 alkoxycarbonyl, aryloxycarbonyl, C1-8 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkanoylamino, aroylamino, C1-8 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino, guanidino, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-8 alkyl, C3-6 cycloalkyl, aryl, arylalkyl, C1-8 alkoxy, aryloxy, arylalkoxy, aroyl, amino, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino,

R₆ is H, C1-8 alkyl, C3-7 cycloalkyl, aryl or cyano, wherein R₆ is optionally substituted to by one or more R_(f);

R_(f) is selected from the group consisting of C1-8 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, arylC1-8alkoxy, heteroarylC1-8alkoxy, C1-8 alkoxycarbonyl, aryloxycarbonyl, C1-8 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkanoylamino, aroylamino, C1-8 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylC1-8 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-8 alkyl, C3-7 cycloalkyl, aryl optionally substituted by one or more groups selected from halogen, methyl or methoxy, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, arylC1-8alkoxy, C1-8 alkoxycarbonyl, aryloxycarbonyl, C1-8 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkanoylamino, aroylamino, C1-8 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino, and guanidino;

or R₅ and R₆ together with the carbon they are attached form a carbocyclic ring of 3 to 6 carbon atoms, the carbocyclic ring being optionally substituted with one or more R_(h);

R_(h) is selected from the group consisting of C1-8 alkyl, aryl, C1-8 alkoxycarbonyl, aryloxycarbonyl, arylC1-8alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with a group selected from C1-8 alkyl, C3-7 cycloalkyl, aryl, arylC1-8alkyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, carboxy, and cyano; and

X is O or S.

More preferred compounds of the formula (IIa) are those wherein:

Y is O or S;

R₁ is C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl, indolinyl, pyranyl and thiopyranyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl or amino; wherein R1 is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-5 alkyl, C3-6 cycloalkyl, aryl, C1-5 alkoxy, aryloxy, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₂ is H or C1-3 alkyl;

R₃ is H, C2-5 alkyl, C3-7 cycloalkyl, aryl wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, C1-5alkanoyl, aroyl, C1-5 alkoxycarbonyl, aryloxycarbonyl C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-5 alkyl, C3-6 cycloalkyl, aryl, arylalkyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, aroyl, amino, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

R₄ is H or C1-3 alkyl

R₅ is H or C1-8 alkyl

R₆ is H, C1-5 alkyl, C3-7 cycloalkyl, aryl or cyano, wherein R₆ is optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, heteroarylC1-5alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylC1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, aryl optionally substituted by one or more groups selected from halogen, methyl or methoxy, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino;

or R₅ and R₆ together with the carbon they are attached form a carbocyclic ring of 3 to 6 carbon atoms, the carbocyclic ring being optionally substituted with one or more R_(h);

R_(h) is selected from the group consisting of C1-5 alkyl, aryl, C1-5 alkoxycarbonyl, aryloxycarbonyl, arylC1-5alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with a group selected from C1-5 alkyl, C3-7 cycloalkyl, aryl, arylC1-5alkyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, carboxy and cyano.

Even more preferred compounds of the formula (IIa) are those wherein:

Y is O;

R₁ is C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl, pyranyl and thiopyranyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl; or amino wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxy, aryloxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by alkyl or aryl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy, cyano and nitro, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-5 alkyl, C3-6 cycloalkyl, aryl, C1-5 alkoxy, aryloxy, halogen, hydroxy, oxo, carboxy and cyano;

R₂ is H or methyl;

R₃ is H, C2-5 alkyl, C3-7 cycloalkyl or phenyl wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxy, aryloxy, aroyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-5 alkyl, C3-6 cycloalkyl, aryl, arylC1-5alkyl, C1-5 alkoxy, aryloxy, arylC1-3alkoxy, aroyl, amino, halogen, hydroxy, oxo, carboxy and cyano;

R₄ is H or methyl;

R₅ is H or C1-5 alkyl;

R₆ is H, C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl or cyano, wherein R₆ is optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, heteroarylC1-5alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylC1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, phenyl optionally substituted by one or more groups selected from halogen, methyl or methoxy, naphthyl optionally substituted by one or more groups selected from halogen, methyl or methoxy, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano;

or R₅ and R₆ together with the carbon they are attached form a carbocyclic ring of 3 to 6 carbon atoms, the carbocyclic ring being optionally substituted with one or more R_(h);

R_(h) is selected from the group consisting of C1-5 alkyl, phenyl, naphthyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, arylC1-3alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with a group selected from C1-5 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, arylC1-3alkyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, carboxy and cyano; and

X is O.

Yet even more preferred compounds of the formula (IIa) are those wherein:

Y is O;

R₁ is C1-5 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl, piperazinyl, pyranyl and thiopyranyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl or amino, wherein R1 is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-3 alkoxy, phenoxy, C1-3 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenylor heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5alkyl, phenyl or naphthyl; C1-5 alkoxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, aryl, C1-3 alkoxy, phenoxy, halogen, hydroxy, oxo, carboxy and cyano;

R₂ is H;

R₃ is C2-5 alkyl, C3-6 cycloalkyl or phenyl, wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, quinolinyl and isoquinolinyl, C1-5 alkoxy, phenoxy, aroyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, C1-5 alkanoylamino, aroylamino, C1-3 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, phenylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-3 alkyl, phenyl or heteroaryl selected the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, C1-5 alkoxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl, phenyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-5 alkyl, C5-6 cycloalkyl, phenyl, naphthyl, arylC1-3alkyl, C1-5 alkoxy, phenoxy, arylC1-3alkoxy, aroyl, amino, halogen, hydroxy, oxo, carboxy and cyano;

R₄ is H;

R₆ is H, C1-5 alkyl, C3-6 cycloalkyl, phenyl or cyano, wherein R₆ is optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxy, aryloxy, arylC1-3alkoxy, heteroarylC1-3alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenylor heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, C1-5 alkanoylamino, aroylamino, C1-3 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylC1-3alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl or phenyl, C1-5 alkoxycarbonylamino, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, halogen, hydroxy, oxo, carboxy and cyano, Rf may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, phenyl optionally substituted by one or more groups selected from halogen or methyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, pyrimidinyl, pyrazinyl and indolyl, C1-5 alkoxy, aryloxy, arylC1-3alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or aryl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl or aryl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or aryl, halogen, hydroxy, oxo, carboxy and cyano;

or R₅ and R₆ together with the carbon they are attached form a carbocyclic ring of 3 to 6 carbon atoms, the carbocyclic ring being optionally substituted with one or more R_(h);

R_(h) is selected from the group consisting of C1-5 alkyl, phenyl, C1-5 alkoxycarbonyl aryloxycarbonyl, arylC1-3alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with C1-5 alkyl, C3-6 cycloalkyl, phenyl, naphthyl or arylC1-3alkyl; halogen, hydroxy, carboxy and cyano.

Still yet even more preferred compounds of the formula(IIa) are those wherein:

R₁ is C1-3 alkyl, C5-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl, piperazinyl, pyranyl and thiopyranyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl or amino, wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, phenyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-3 alkoxy, C1-3 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl, phenylor heteroaryl selected from the group consisting of pyrrolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl and benzthiazolyl C1-5 alkanoylamino, aroylamino, C1-3 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-3alkyl or phenyl, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3alkyl, phenyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of pyrrolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, C1-3 alkoxy, halogen and hydroxy;

R₃ is C2-5 alkyl, C5-6 cycloalkyl or phenyl wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, 4-piperidinyl, 4-morpholinyl, piperazinyl, furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, C1-5 alkoxy, phenoxy, aroyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or phenyl, C1-5 alkanoylamino, C1-3 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-3 alkyl or phenyl, C1-5 alkoxycarbonylamino, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl, halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-5 alkyl, C5-6 cycloalkyl, phenyl, benzyl, C1-5 alkoxy, phenoxy, benzyloxy, aroyl, halogen, hydroxy, oxo, carboxy and cyano;

R₅ is H or C1-3alkyl;

R₆ is H, C1-5 alkyl, phenyl or cyano, wherein R₆ is optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, C1-3 alkoxy, benzyloxy, pyridylC1-3alkoxy, thienylC1-3 alkoxy, furanylC1-3 alkoxy, C1-3 alkoxycarbonyl, phenoxyoxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl, C1-5 alkanoylamino, aroylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl or phenyl, C1-3 alkoxycarbonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or phenyl, halogen, hydroxy, oxo, carboxy and cyano, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-3 alkyl, phenyl optionally substituted by one or more groups selected from the group consisting of halogen and methyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl and pyridinyl, C1-3 alkoxy, aryloxy, benzyloxy, C1-5 alkoxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or phenyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom may be independently substituted by C1-5 alkyl or phenyl C1-5 alkoxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-3 alkylsulfonylamino, arylsulfonylamino C1-3 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl, halogen hydroxy, oxo, carboxy and cyano;

or R₅ and R₆ together with the carbon they are attached form a carbocyclic ring of3 to 5 carbon atoms, the carbocyclic ring being optionally substituted with one or more R_(h);

R_(h) is selected from the group consisting of C1-3 alkyl, phenyl, C1-3 alkoxycarbonyl, phenoxyoxycarbonyl, benzyloxy, carbamoyl wherein the nitrogen atom may be optionally mono or di-substituted with a group selected from the group consisting of C1-5 alkyl, phenyl and benzyl, halogen, hydroxy carboxy and cyano.

Even more preferred compounds of the formula (IIa) are those wherein:

R₁ is C5-6 cycloalkyl, phenyl, naphthyl, piperidinyl, morpholinyl, piperazinyl, pyranyl, thiopyranyl, furanyl, thienyl, pyrrolyl or amino, wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, phenyl, furanyl, thienyl, pyrrolyl, imidazolyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, C1-3 alkoxy, C1-3 alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl; C1-5 alkanoylamino, aroylamino, ureido wherein either nitrogen atom may be independently substituted by C1-3alkyl or phenyl; C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3alkyl or phenyl, halogen, hydroxy, oxo, carboxy and cyano, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-3alkyl, C1-3alkoxy, halogen and hydroxy;

R₃ is C2-5 alkyl, C5-6 cycloalkyl or phenyl, wherein R₃ is optionally substituted by one or more groups of the formula R_(d); R_(d) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, 4-piperidinyl, furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, C1-3 alkoxy, C1-5 alkoxycarbonyl, C1-5 alkanoyloxy, benzoyloxy, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl, C1-5 alkanoylamino, C1-3 alkylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, C1-3 alkoxycarbonylamino, C1-3 alkylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl, halogen hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of C1-3 alkyl, phenyl, benzyl, C1-3 alkoxy, phenoxy, benzyloxy, benzoyl, halogen, hydroxy, oxo, carboxy and cyano;

wherein the configuration at the stereocenter defined by R₂ and R₃ and the carbon they are attached to is defined as L;

R₅ is H or methyl;

R₆ is C1-5 alkyl, phenyl or cyano wherein R₆ is optionally substituted by one or more groups of the formula R_(f);

R_(f) is selected from the group consisting of methyl C3-6 cycloalkyl, phenyl, naphthyl, furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, C1-3 alkoxy, benzyloxy, pyridylC1-3alkoxy, thienylC1-3alkoxy, furanylC1-3 alkoxy, C1-5 alkanoylamino, aroylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, C1-3 alkoxycarbonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-5 alkyl or phenyl, halogen, hydroxy, oxo, carboxy and cyano, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of C1-3 alkyl, phenyl optionally substituted by one or more groups selected from halogen or methyl, C1-3 alkoxy, aryloxy, benzyloxy, C1-3 alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl, C1-5 alkanoylamino, aroylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl, halogen, hydroxy, oxo, carboxy and cyano;

or R₅ and R₆ together with the carbon they are attached form a carbocyclic ring of 3 to 5 carbon atoms, the carbocyclic ring being optionally substituted with one or more R_(h);

R_(h) is selected from the group consisting of C1-3 alkyl, phenyl, C1-3 alkoxycarbonyl, benzyloxy and carboxy.

Much more preferred compounds of formula (IIa) are those wherein:

R₁ is cyclohexyl, phenyl, naphthyl, piperidinyl, morpholinyl, piperazinyl, pyranyl, thiopyranyl or amino wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, phenyl, furanyl, thienyl, pyrrolyl, imidazolyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, C1-3 alkoxy, C1-3 alkoxycarbonyl, carbamoyl wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl, halogen, hydroxy, oxo, carboxy and cyano, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of C1-3 alkoxy, halogen and hydroxy,

R₃ is C2-5 alkyl or C5-6 cycloalkyl wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of methyl, C3-6 cycloalkyl, phenyl, naphthyl, thienyl, imidazolyl, pyridinyl, indolyl, C1-4 alkoxy, C1-5 alkanoylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of methyl, phenyl, benzyl, methoxy, phenoxy, benzyloxy, benzoyl, halogen and hydroxy;

R₆ is C1-5 alkyl or phenyl, wherein R₆ is optionally substituted by one or more R_(f);

R_(f) is selected from the group consisting of C3-6 cycloalkyl, phenyl, naphthyl, thienyl, imidazolyl, pyridinyl, indolyl, methoxy, benzyloxy, C1-3 alkanoylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, methoxycarbonylamino, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl, halogen, hydroxy, carboxy and cyano, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of methyl, phenyl optionally substituted by one or more groups selected from halogen or methyl, methoxy, phenoxy, benzyloxy, methoxycarbonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl or phenyl, halogen, hydroxy and carboxy;

or R₅ and R₆ together with the carbon they are attached form a carbocyclic ring of 3 to 5 carbon atoms, the carbocyclic ring being optionally substituted with one or more R_(h);

R_(h) is selected from the group consisting of vinyl, phenyl, methoxycarbonyl, benzyloxycarbonyl and carboxy;

Penultimately preferred compounds of the formula (IIa) are those wherein:

R₁ is cyclohexyl, phenyl, naphthyl, piperidinyl, morpholinyl, piperazinyl, pyranyl or thiopyranyl, wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of pyrrolyl, imidazolyl, indolyl, benzimidazolyl, methoxy, methoxycarbonyl, amino wherein the nitrogen atom may be independently mono or di-substituted by C1-3 alkyl, halogen, hydroxy and carboxy, R_(b) may be further optionally substituted by one or more R_(c);

R_(c) is selected from the group consisting of methoxy, halogen and hydroxy;

R_(d) is selected from the group consisting of methyl, C3-6 cycloalkyl, phenyl, naphthyl, C1-4 alkoxy, C1-3 alkanoylamino, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, halogen, hydroxy, oxo, carboxy and cyano, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of methyl, phenyl, methoxy, halogen and hydroxy;

R₅ is H;

R_(f) is selected from the group consisting of C5-6 cycloalkyl, phenyl, naphthyl, thienyl, indolyl, methoxy, benzyloxy, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, methoxycarbonylamino, halogen, hydroxy, carboxy and cyano, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of methyl, phenyl optionally substituted by halogen, methoxy, phenoxy, benzyloxy, methoxycarbonyl, halogen, hydroxy and carboxy;

or R₅ and R₆ together with the carbon they are attached form a carbocyclic ring of 3 carbon atoms, the carbocyclic ring being optionally substituted with one or more R_(h);

R_(h) is vinyl or phenyl.

Ultimately preferred compounds of formula (IIa) are those wherein:

R₁ is phenyl, naphthyl or 4-morpholinyl wherein R₁ is optionally substituted by one or more R_(b);

R_(b) is selected from the group consisting of benzimidazolyl, methoxy and dimethylamino R_(b) may be further optionally substituted by R_(c) wherein R_(c) is a halogen atom;

R₃ is C2-5 alkyl wherein R₃ is optionally substituted by one or more R_(d);

R_(d) is selected from the group consisting of C3-6 cycloalkyl, phenyl or naphthyl, R_(d) may be further optionally substituted by one or more R_(e);

R_(e) is selected from the group consisting of methyl and halogen,

R_(f) is selected from the group consisting of C5-6 cycloalkyl, phenyl, naphthyl, indolyl, benzyloxy, methylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom may be oxidized to a sulfoxide or sulfone, halogen and carboxy, R_(f) may be further optionally substituted by one or more R_(g);

R_(g) is selected from the group consisting of methyl, methoxy, methoxycarbonyl, halogen and hydroxy and

R₅ and R₆ together with the carbon they are attached form a carbocyclic ring of 3 carbon atoms, the carbocyclic ring being optionally substituted with one or more R_(h).

The following are representative compounds according to the invention:

N-(4-morpholylinecarbonyl)-L-leucine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-Homophenylalanine(1S-cyano-3-phenylpropyl)amide;

N-(5-dimethylaminonaphth-1-ylsulfonyl)-L-leucine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine-(1S-cyano-3-phenylpropyl)-N-methylamide;

N-(4-Morpholinecarbonyl)-L-leucine-[1R,S(benzthiazol-2-ylcarbonyl)-3-phenylpropyl]amide;

N-[(4-Morpholinecarbonyl]-L-leucine-[1R,S-(thiazol-2-ylcarbonyl)-3-phenylpropyl]amide,

N-(4-Morpholinecarbonyl)-L-leucine-[1R,S-[(1-(3-N-Benzyl)imidazol-2-ylcarbonyl]-3-phenylpropyl]amide;

N-(4-Morpholinecarbonyl)-L-leucine-[1R,S-(2-imidazolylcarbonyl)-3-phenylpropyl]amide;

N-(4-morpholinecarbonyl)-L-leucine (cyanomethyl)amide;

N-(4-Morpholinecarbonyl)-L-leucine [1S-cyano-5-((benzyloxycarbonyl)-amino)-pentyl]amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-3-phenylpropyl)amide;

N-(4-Morpholinecarbonyl]-L-leucine-(1S-cyano-5-aminopentyl)amide;

N-(4-morpholinecarbonyl]-L-phenylalanine-(1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-(p-ethoxy)phenylalanine-(1S-cyano-3-phenylpropyl)amide;

N-(4-Morpholinecarbonyl)-L-leucine-[1S-cyano-4-(benzyloxycarbonylamino)-butyl]amide;

N-(4-Morpholinecarbonyl)-L-leucine-[1-(benzthiazol-2-ylcarbonyl)-5-[(benzyloxycarbonyl)amino]-pentyl]amide;

N-(1-naphthylsulfonyl)-L-leucine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-(4-methyl)leucine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-benzyloxyethyl)amide;

N-(methanesulfonyl)-D-(O-benzyl)serine (1S-cyano-3-phenylpropyl)amide;

N-(5-dimethylaminonaphth-1-ylsulfonyl)-D-leucine (1R-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-(4-methyl)leucine (1R-cyano-2-benzyloxyethyl)amide;

N-((4-dimethylaminophenyl)sulfonyl)-L-leucine (1S-cyano-3-(phenylpropyl))amide;

N-(t-Butoxycarbonyl)-L-leucine [1-(Benzothiazo-2-ylcarbonyl)-3 -phenylpropyl]amide;

N-(5-dimethylaminonaphth-1-ylsulfonyl)-L-leucine [1-(Benzothiazol-2-ylcarbonyl)-3-phenylpropyl]amide;

N-(4-methoxy-phenylsulfonyl)-L-leucine [1-(Benzothiazol-2-ylcarbonyl)-3-phenylpropyl]amide;

N-(4-Morpholinecarbonyl)-L-leucine-[1R,S(benzoxazol-2-ylcarbonyl)-3-phenylpropyl]amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2R-benzyloxypropyl)amide;

N-(4-Morpholinecarbonyl)-L-leucine-[1R,S-[(4-phenylthiazol-2-yl)-carbonyl]-3-phenylpropyl]amide;

N-(4-morpholinecarbonyl)-D-leucine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine [[1-[(6-phenylcarbamoyl)benzothiazol-2-ylcarbonyl]-3-phenylpropyl]]amide;

N-(methylsulfonyl)-L-leucine [1-(Benzothiazol-2-ylcarbonyl)-3-phenylpropyl]amide;

N-(4-morpholinecarbonyl)-L-(p-phenyl)phenylalanine (1S-cyano-3-phenylpropyl)amide;

N-(4-Morpholinecarbonyl)-L-leucine-[1R,S-[(5-phenylthiazol-2-yl)-carbonyl]-3-phenylpropyl]amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(benzylsulfanyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(2-chlorophenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylglycine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine [1-(Benzothiazol-2-ylcarbonyl)-2-benzyloxyethyl]amide;

N-(4-Morpholinecarbonyl]-L-leucine-[[6-(carbomethoxy)-benzoxazol-2-ylcarbonyl]-3-phenylpropyl]amide;

N-(5-dimethylaminonaphth-1-ylsulfonyl)-L-(4-methyl)leucine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-cyclohexylalanine (1S-cyano-3-phenylpropyl)amide;

N-(4-Morpholinecarbonyl)-L-leucine-[1R,S-[(4-(4-benzyloxycarbonylamino)phenyl-thiazol-2-yl)-carbonyl]-3-phenylpropyl]amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(3-methoxyphenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-(4-methyl)leucine (1R-cyano-2-(benzylsulfanyl)ethyl)amide:

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(benzylsulfonyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(benzylsulfinyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-((4-methoxyphenyl)methylsulfanyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-((4-methylphenyl)methylsulfanyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(4-chlorophenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(3-chlorophenyl)methyloxyethyl)amide;

N-(5-dimethylaminonaphth-1-ylsulfonyl)-L-leucine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-Morpholinecarbonyl]-L-leucine 1S-((2-phenyloxazol-5-yl)carbonyl)-3-phenylpropylamide;

N-(4-morpholinecarbonyl)-L-(p-phenylcarbonyl)phenylalanine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(2-methylphenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(3-methylphenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(4-methylphenyl)methyloxyethyl)amide;

N-(4-Morpholinecarbonyl]-L-leucine 1RS-((5-phenyloxazol-2-yl)carbonyl)-3-phenylpropylamide;

N-(4-morpholinecarbonyl)-L-cyclohexylalanine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-nor-leucine (1S-cyano-3-phenylpropyl)amide;

N-(Benzyloxycarbonyl)-L-(O-t-butyl)serine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-Morpholinecarbonyl]-L-leucine 1S-(oxazol-2-ylcarbonyl)-3-phenylpropylamide;

N-(4-morpholinecarbonyl)-L-(4-methyl)leucine [1-(Benzothiazol-2-ylcarbonyl)-3-phenylpropyl]amide

N-(5-dimethylaminonaphth-1-ylsulfonyl)-L-cyclohexylalanine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(3-carbomethoxyphenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(4-carbomethoxyphenyl)methyloxyethyl)amide;

N-(4-Morpholinecarbonyl]-L-leucine 1S-(pyrid-2-ylcarbonyl)-3-phenylpropylamide;

N-(4-Morpholinecarbonyl)-L-leucine-[1R,S-[(4-(2-benzyloxyamino)phenyl-thiazol-2-yl)-carbonyl]-3-phenylpropyl]amide;

N-(4-morpholinecarbonyl)-L-(O-t-butyl)serine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-hydroxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-3-(carbo-t-butoxy)propyl)amide;

N-(cyclohexylcarbonyl)-L-leucine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-3-(carbo-t-butoxy)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine dicyanomethylamide;

N-(4-morpholinecarbonyl)-L-(2-naphthyl)alanine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-(O-Benzyl)glutamate (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-homo-tyrosine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-norvaline (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-(2-chlorophenyl)alanine (1S-cyano-3-phenylpropyl)amide;

N-Benzoyl-L-leucine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-(4,5-dehydro)leucine(1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-(O-methyl)tyrosine(1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-iso-leucine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-(4-nitrophenyl)alanine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-(4-fluorophenyl)alanine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-tyrosine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-(1-naphthyl)alanine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-methionine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(1-benzyl-4-imidazolyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(1-benzyl-4-imidazolyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(carbobenzyloxy)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine(1S-cyano-2-(carbobenzyloxy)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-1-phenylmethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-1-phenylmethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(4-benzyloxyphenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(4-benzyloxyphenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1-cyanocyclopropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1-cyanocyclopropyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(4-phenylphenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(4-phenylphenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(4-benzoylphenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine(1S-cyano-2-(4-benzoylphenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(1-naphthyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(1-naphthyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(2-naphthyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(2-naphthyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(2-chlorophenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(2-chlorophenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(4-chlorophenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(4-chlorophenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(3,4-dichlorophenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(3,4-dichlorophenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyanobut-3-ynyl)amide;

N-(4-morpholinecarbonyl)-L-leucine(1S-cyanobut-3-ynyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyanopropyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(4-(2,6-dichloromethyloxy)phenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2S-methylbutyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyanopentyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyanopentyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2,2-dimethylpropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2,2-dimethylpropyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-3-methylbutyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-3-methylbutyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(4-nitrophenylethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(4-nitrophenylethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyanobutyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyanobutyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1R-cyano-2R-benzyloxypropyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyanoethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyanoethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-3-(carbobenzyloxy)propyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-3-(carbobenzyloxy)propyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(3-benzimidazolyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(3-benzimidazolyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1-cyano-1-methylethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1-cyano-1-methylethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(4-hydroxyphenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(4-hydroxyphenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S,3-dicyanopropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S,3-dicyanopropyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(4-hydroxy-3-iodophenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(4-hydroxy-3-iodophenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S,2-dicyanoethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S,2-dicyanoethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(2-thienyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(2-thienyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-3-(methylsulfonyl)propyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-3-(methylsulfonyl)propyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-phenylethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-phenylethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-3-(4-hydroxyphenyl)propyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-3-(4-hydroxyphenyl)propyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-cyclohexylethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-cyclohexylethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(3-chlorophenyl)ethyl)amide; and

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(3-chlorophenyl)ethyl)amide.

Preferred Compounds of the Invention Include

N-(5-dimethylaminonaphth-1-ylsulfonyl)-L-leucine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-3-phenylpropyl)amide;

N-(1-naphthylsulfonyl)-L-leucine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-(4-methyl)leucine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-(4-methyl)leucine (1R-cyano-2-benzyloxyethyl)amide;

N-((4-dimethylaminophenyl)sulfonyl)-L-leucine (1S-cyano-3-(phenylpropyl))amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2R-benzyloxypropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(benzylsulfanyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(2-chlorophenyl)methyloxyethyl)amide;

N-(5-dimethylaminonaphth-1-ylsulfonyl)-L-(4-methyl)leucine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(3-methoxyphenyl)methyloxyethyl)amide:

N-(4-morpholinecarbonyl)-L-(4-methyl)leucine (1R-cyano-2-(benzylsulfanyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(benzylsulfonyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(benzylsulfinyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-((4-methoxyphenyl)methylsulfanyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-((4-methylphenyl)methylsulfanyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(4-chlorophenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(3-chlorophenyl)methyloxyethyl)amide;

N-(5-dimethylaminonaphth-1-ylsulfonyl)-L-leucine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(2-methylphenyl)methyloxyethyl)amide;

N(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(3-methylphenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(4-methylphenyl)methyloxyethyl)amide;

N-(5-dimethylaminonaphth-1-ylsulfonyl)-L-cyclohexylalanine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(3-carbomethoxyphenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(4-carbomethoxyphenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-hydroxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-3-(carbo-t-butoxy)propyl)amide;

N-(cyclohexylcarbonyl)-L-leucine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-3-(carbo-t-butoxy)ethyl)amide;

N-(4-morpholylinecarbonyl)-L-leucine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-Homophenylalanine(1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (cyanomethyl)amide;

N-(4-Morpholinecarbonyl)-L-leucine [1S-cyano-5-((benzyloxycarbonyl)-amino)-pentyl]amide;

N-(4-Morpholinecarbonyl]-L-leucine-(1S-cyano-5-aminopentyl)amide;

N-(4-morpholinecarbonyl]-L-phenylalanine-(1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-(p-ethoxy)phenylalanine-(1S-cyano-3-phenylpropyl)amide;

N-(4-Morpholinecarbonyl)-L-leucine-[1S-cyano-4-(benzyloxycarbonylamino)-butyl]amide;

N-(4-Morpholinecarbonyl)-L-leucine-[1R,S(benzthiazol-2-ylcarbonyl)-3-phenylpropyl]amide;

N-(4-Morpholinecarbonyl)-L-leucine-[1R,S(benzoxazol-2-ylcarbonyl)-3-phenylpropyl]amide;

N-(4-Morpholinecarbonyl)-L-leucine-[1-(benzthiazol-2-ylcarbonyl)-5-[(benzyloxycarbonyl)amino]-pentyl]amide;

N-(4-Morpholinecarbonyl]-L-leucine-[[6-(carbomethoxy)-benzoxazol-2-ylcarbonyl]3-phenylpropyl]amide;

N-(4-morpholinecarbonyl)-L-leucine [[1-[(6-phenylcarbamoyl)benzothiazol-2-ylcarbonyl]-3-phenylpropyl]]amide;

N-(4-morpholinecarbonyl)-L-(p-phenyl)phenylalanine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-phenylglycine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-cyclohexylalanine (1S-cyano-3-phenylpropyl)amide;

N-(4-Morpholinecarbonyl]-L-leucine 1S-((2-phenyloxazol-5-yl)carbonyl)-3-phenylpropylamide;

N-(4-morpholinecarbonyl)-L-(p-phenylcarbonyl)phenylalanine (1S-cyano-3-phenylpropyl)amide;

N-(4-Morpholinecarbonyl]-L-leucine 1RS-((5-phenyloxazol-2-yl)carbonyl)-3-phenylpropylamide;

N-(4-Morpholinecarbonyl]-L-leucine 1S-(oxazol-2-ylcarbonyl)-3-phenylpropylamide;

N-(4-morpholinecarbonyl)-L-cyclohexylalanine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-nor-leucine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-(4-methyl)leucine [1-(Benzothiazol-2-ylcarbonyl)-3-phenylpropyl]amide

N-(4-Morpholinecarbonyl]-L-leucine 1S-(pyrid-2-ylcarbonyl)-3-phenylpropylamide;

N-(4-morpholinecarbonyl)-L-(O-t-butyl)serine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-(2-naphthyl)alanine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-(O-Benzyl)glutamate (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-homo-tyrosine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-norvaline (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-(2-chlorophenyl)alanine (1S-cyano-3-phenylpropyl)amide;

N-Benzoyl-L-leucine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-(4,5-dehydro)leucine(1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-(O-methyl)tyrosine(1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-iso-leucine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-(4-nitrophenyl)alanine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-(4-fluorophenyl)alanine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-tyrosine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-(1-naphthyl)alanine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-methionine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(1-benzyl-4-imidazolyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(1-benzyl-4-imidazolyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(carbobenzyloxy)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine(1S-cyano-2-(carbobenzyloxy)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-1-phenylmethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-1-phenylmethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(4-benzyloxyphenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(4-benzyloxyphenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1-cyanocyclopropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1-cyanocyclopropyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(4-phenylphenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(4-phenylphenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(4-benzoylphenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine(1S-cyano-2-(4-benzoylphenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(1-naphthyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(1-naphthyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(2-naphthyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(2-naphthyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(2-chlorophenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(2-chlorophenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(4-chlorophenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(4-chlorophenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(3,4-dichlorophenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(3,4-dichlorophenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyanobut-3-ynyl)amide;

N-(4-morpholinecarbonyl)-L-leucine(1S-cyanobut-3-ynyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyanopropyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(4-(2,6-dichloromethyloxy)phenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(4-(2,6-dichloromethyloxy)phenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2S-methylbutyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyanopentyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyanopentyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2,2-dimethylpropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2,2-dimethylpropyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-3-methylbutyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-3-methylbutyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(4-nitrophenylethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(4-nitrophenylethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyanobutyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyanobutyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1R-cyano-2R-benzyloxypropyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyanoethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyanoethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-3-(carbobenzyloxy)propyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-3-(carbobenzyloxy)propyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(3-benzimidazolyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(3-benzimidazolyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1-cyano-1-methylethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1-cyano-1-methylethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(4-hydroxyphenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(4-hydroxyphenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S,3-dicyanopropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S,3-dicyanopropyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(4-hydroxy-3-iodophenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(4-hydroxy-3-iodophenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S,2-dicyanoethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S,2-dicyanoethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(2-thienyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(2-thienyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-3-(methylsulfonyl)propyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-3-(methylsulfonyl)propyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-phenylethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-phenylethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-3-(4-hydroxyphenyl)propyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-3-(4-hydroxyphenyl)propyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-cyclohexylethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-cyclohexylethyl)amide;

N-(4-morpholinecarbonyl)-L-phenylalanine (1S-cyano-2-(3-chlorophenyl)ethyl)amide; and

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(3-chlorophenyl)ethyl)amide.

More Preferred Compounds of the Invention Include:

N-(4-morpholinecarbonyl)-L-(4-methyl)leucine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-(4-methyl)leucine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2R-benzyloxypropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(benzylsulfanyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(2-chlorophenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(4-chlorophenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(3-methoxyphenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-(4-methyl)leucine (1R-cyano-2-(benzylsulfanyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(benzylsulfonyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(benzylsulfinyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-((4-methoxyphenyl)methylsulfanyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(3-chlorophenyl)methyloxyethyl)amide;

N-(5-dimethylaminonaphth-1-ylsulfonyl)-L-leucine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(2-methylphenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(3-methylphenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(4-methylphenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(3-carbomethoxyphenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(4-carbomethoxyphenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-3-(carbo-t-butoxy)propyl)amide;

N-(4-morpholylinecarbonyl)-L-leucine (1S-cyano-3-phenylpropyl)amide;

N-(4-Morpholinecarbonyl)-L-leucine-[1S(benzthiazol-2-ylcarbonyl)-3-phenylpropyl]amide;

N-(4-Morpholinecarbonyl)-L-leucine [1S-cyano-5-((benzyloxycarbonyl)-amino)-pentyl]amide;

N-(4-Morpholinecarbonyl)-L-leucine-[1R,S(benzoxazol-2-ylcarbonyl)-3-phenylpropyl]amide;

N-(4-morpholinecarbonyl)-L-leucine [[1-[(6-phenylcarbamoyl)benzothiazol-2-ylcarbonyl]-3-phenylpropyl]]amide;

N-(4-Morpholinecarbonyl]-L-leucine-[[6-(carbomethoxy)-benzoxazol-2-ylcarbonyl]-3-phenylpropyl]amide;

N-(4-morpholinecarbonyl)-L-cyclohexylalanine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-cyclohexylalanine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-nor-leucine (1S-cyano-3-phenylpropyl)amide,

N-(4-Morpholinecarbonyl]-L-leucine 1R,S-((5-phenyloxazol-2-yl)carbonyl)-3-phenylpropylamide;

N-(4-Morpholinecarbonyl]-L-leucine 1S-(oxazol-2-ylcarbonyl)-3-phenylpropylamide;

N-(4-morpholinecarbonyl)-L-(4-methyl)leucine [1-(Benzothiazol-2-ylcarbonyl)-3-phenylpropyl]amide;

N-(4-morpholinecarbonyl)-L-(2-naphthyl)alanine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-(2-chlorophenyl)alanine (1S-cyano-3-phenylpropyl)amide;

N-Benzoyl-L-leucine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-(O-methyl)tyrosine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine(1S-cyano-2-(carbobenzyloxy)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-1-phenylmethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1-cyanocyclopropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(2-chlorophenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(4-(2,6-dichloromethyloxy)phenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-3-(carbobenzyloxy)propyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S,3-dicyanopropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S,2-dicyanoethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-3-(methylsulfonyl)propyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-3-(4-hydroxyphenyl)propyl)amide; and

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-cyclohexylethyl)amide.

Any compounds of this invention containing one or more asymmetric carbon atoms may occur as racemates and racemic mixtures, single enantiomers, diastereomeric mixtures and individual diastereomers. All such isomeric forms of these compounds are expressly included in the present invention. Each stereogenic carbon may be in the R or S configuration, or a combination of configurations.

Some of the compounds of formulas (I), (Ia) and formulas (II), (IIa) can exist in more than one tautomeric form, The invention includes all such tautomers.

It shall be understood by one of ordinary skill in the art that all compounds of the invention are those which are chemically stable.

The invention includes pharmaceutically acceptable derivatives of compounds of formulas (I), (Ia) and formulas (II), (IIa). A “pharmaceutically acceptable derivative” refers to any pharmaceutically acceptable salt or ester of a compound of this invention, or any other compound which, upon administration to a patient, is capable of providing (directly or indirectly) a compound of this invention, a pharmacologically active metabolite or pharmacologically active residue thereof. A pharmacologically active metabolite shall be understood to mean any compound of the invention capable of being metabolized enzymatically or chemically, This includes, for example, hydroxylated or oxidized derivative compounds of the invention.

In addition, the compounds of this invention include prodrugs of compounds of the formulas (I),(Ia) and formulas (II), (IIa). Prodrugs include those compounds that, upon simple chemical transformation, are modified to produce the compounds of the invention. Simple chemical transformations include hydrolysis, oxidation and reduction. Specifically, when a prodrug of this invention is administered to a patient, the prodrug may be transformed into a compound of formulas (I),(Ia) or formulas (II), (IIa), thereby imparting the desired pharmacological effect.

In order that the invention herein described may be more fully understood, the following detailed description is set forth. As used herein, the following abbreviations are used:

BOC or t-BOC is tertiary butoxycarbonyl;

t-Bu is tertiary butyl;

DMF is dimethylformamide;

EtOAc is ethyl acetate;

THF is tetrahydrofuran;

Ar is argon;

TFA is trifluoroacetic acid:

EDC is 1-(3-dimethylaminopropyl)-3-ethylcarbodimide hydrochloride.

HOBT is 1-hydroxybenzotriazole

Also, as used herein, each of the following terms, used alone or in conjunction with other terms, are defined as follows (except where noted to the contrary):

The term “alkyl” refers to a saturated aliphatic radical containing from one to ten carbon atoms or a mono- or polyunsaturated aliphatic hydrocarbon radical containing from two to twelve carbon atoms, containing at least one double or triple bond, respectively, “Alkyl” refers to both branched and unbranched alkyl groups. Preferred alkyl groups are straight chain alkyl groups containing from one to eight carbon atoms and branched alkyl groups containing from three to eight carbon atoms. More preferred alkyl groups are straight chain alkyl groups containing from one to six carbon atoms and branched alkyl groups containing from three to six carbon atoms. It should be understood that any combination term using an “alk” or “alkyl” prefix refers to analogs according to the above definition of “alkyl”. For example, terms such as “alkoxy”, “alkythio” refer to alkyl groups linked to a second group via an oxygen or sulfur atom, “Alkanoyl refers to an alkyl group linked to a carbonyl group (C═O),

The term “cycloalkyl” refers to the cyclic analog of an alkyl group, as defined above, Preferred cycloalkyl groups are saturated cycloalkyl groups containing from three to eight carbon atoms, and more preferably three to six carbon atoms.

The term “aryl” refers to phenyl and naphthyl. “Aroyl” refers to an aryl group linked to a carbonyl group (C═O).

The term “halo” refers to a halogen radical selected from fluoro, chloro, bromo or iodo. Preferred halo groups are fluoro, chloro and bromo.

The term “heteroaryl” refers to a stable 5-8 membered (but preferably, 5 or 6 membered) monocyclic or 8-11 membered bicyclic aromatic heterocycle radical. Each heterocycle consists of carbon atoms and from 1 to 4 heteroatoms selected from the group consisting of nitrogen, oxygen and sulfur. As used herein “nitrogen” and “sulfur” include any oxidized form of nitrogen and sulfur and the quaternized form of any basic nitrogen. The heterocycle may be attached by any atom of the cycle, which results in the creation of a stable structure. Preferred heteroaryl radicals include, for example, furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolizinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, indazolyl, benzimidazolyl, benzthiazolyl, benzoxazolyl, purinyl, quinolizinyl, quinolinyl, isoquinolinyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, naphthyridinyl, pteridinyl, carbazolyl, acridinyl, phenazinyl, phenothiazinyl or phenoxazinyl.

The term “heterocycle” refers to a stable 5-8 membered (but preferably, 5 or 6 membered) monocyclic or 8-11 membered bicyclic heterocycle radical which may be either saturated or unsaturated, and is non-aromatic. Each heterocycle consists of carbon atoms and from 1 to 4 heteroatoms selected from the group consisting of nitrogen, oxygen and sulfur. As used herein, “nitrogen” and “sulfur” include any oxidized form of nitrogen and sulfur and the quaternized form of any basic nitrogen. The heterocycle may be attached by any atom of the cycle, which results in the creation of a stable structure. Preferred heterocycle radicals include, for example, pyrrolinyl, pyrrolidinyl, pyrazolinyl, pyrazolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, pyranyl, thiopyranyl, piperazinyl and indolinyl.

General Synthetic Methods

The invention also provides processes of making the present novel compounds. Compounds of the invention may be prepared by methods described below. Standard peptide coupling, protection and deprotection reactions (see for example M. Bodanszky, The Practice of Peptide Synthesis, Springer-Verlag, 1984) are employed in these syntheses.

Compounds of the invention having formula (II) or (IIa) (nitriles) may be prepared by Method A (Scheme I)

According to Method A a suitably protected amino acid bearing R₆ is allowed to react with ammonia under standard coupling conditions. An example of a suitable protecting group is the t-butoxycarbonyl (Boc) group, An example of standard coupling conditions would be combining the starting materials in the presence of a coupling reagent such as 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) with 1-hydroxybenzotriazole (HOBT), in a suitable solvent such as DMF or methylene chloride. A base such as N-methylmorpholine may be added. This is followed by deprotection to give amino acid amide III. An amino acid ester bearing R₂ and R₃ is then reacted with an acid chloride bearing R₁ in the presence of a suitable base such as N,N-diisopropylethylamine. Conversion to the carboxylic acid provides IV. Standard peptide coupling of III and IV, followed by dehydration of the amide provides the desired nitrile II or IIa. An example of suitable dehydration conditions is cyanuric chloride in DMF.

In a variation (Method B) illustrated in Scheme II, an amino acid amide bearing R₆ is coupled with an amine-protected amino acid bearing R₂ and R₃. A suitable protecting group and coupling conditions would be as described above. Deprotection is then followed by reaction with an acid chloride bearing R₁. Conversion of the amide to the nitrile as above provides II or IIa.

Compounds of the invention having formulas (I) or (Ia) (ketones) may be prepared by Methods C (Scheme III) or D (Scheme IV) as described below.

According to Method C, a suitably protected (for example Boc protected) amino acid is coupled with N,O-dimethylhydroxylamine under standard coupling conditions, such as with carbonyldiimidazole (CDI) in a solvent such as DMF, to give the corresponding amide. This is reduced to the aldehyde (V) with a suitable reducing agent such as LiAlH₄, in a suitable solvent such as THF.

The aldehyde (V) is reacted with the anion of a heterocycle R₈, which is generated by reacting R₈ with a strong base such as n-BuLi in a solvent such as THF at a temperature of about −30° C. to −100° C. and preferably at about −78° C. This is followed by removal of the protecting group providing alcohol (VI). This is coupled with (IV), prepared as described in Scheme I, under standard coupling conditions such as EDC and HOBT in DMF in the presence of a base such as N-methylmorpholine to provide (VII). Oxidation of (VII) with, for example, the Dess Martin Reagent (1,1,1-triacetoxy-1,1-dihydro-1,2-benziodoxol-3(1H)-one) in methylene chloride and t-BuOH, provides the desired ketone of formulas (I) or (Ia).

In Method D, a suitably protected amino acid N-methoxy-N-methylamide (prepared as described in Scheme III) is treated with the anion of a heterocycle R₈, generated by reacting R₈ with a strong base such as n-BuLi in a suitable solvent such as THF at a temperature of about −30° C. to −100° C. and preferably at about −78° C. Deprotection of the resulting ketone provides (VIII). This is coupled with (IV), which is prepared as described in Scheme I, under standard coupling conditions such as EDC and HOBT in DMF in the presence of a base such as N-methylmorpholine to provide the desired ketone of formulas (I) or (Ia).

Compounds of the invention where A is a bond (formulas I, Ia and II, IIa) could be prepared in analogous fashion to the Schemes above by using R₁X, where X=Br, Cl, or I, instead of an acyl halide (R₁C(O)Cl) in Schemes I and II, or by using R₁NHC(R₂)(R₃)CO₂H instead of (IV) in Schemes III and IV.

Intermediates used in Schemes I-IV are either commercially available or easily prepared by methods known to those skilled in the art. A procedure (Method E) that is useful for preparing substituted oxazoles which may be used as R₈ in Scheme III and IV (Methods C and D) is illustrated below in Scheme V.

An N-protected amino acid, for example a t-Boc protected amino acid (IX) is coupled with N,O-dimethylhydroxylamine using a suitable coupling agent, such as carbonyldiimidazole (CDI), in a suitable solvent, such as CH₂Cl₂, THF or DMF, at about 0° C. to provide (X). The N-protecting group is then removed, for example the t-Boc group may be removed by treatment with a suitable acid, such as trifluoroacetic acid, in a suitable solvent, such as CH₂Cl₂. The resulting amine is coupled with the desired carboxylic acid using suitable coupling conditions, such as EDC with HOBT in a suitable solvent such as DMF, in the presence of a base such as N-methylmorpholine to provide a diamide (XI). The N-methoxy-methyl amide is then treated with a suitable reducing agent, such as LiAlH₄ in a suitable solvent, such as THF, to provide an aldehyde (XII). Cyclodehydration (see for example P. Wipf and S. Lim, J. Amer. Chem. Soc, 1995, 117, 558) of (XII) with triphenylphosphine and hexachloroethane in a suitable solvent, such as acetonitrile in the presence of a suitable base, such as Et₃N provides the desired oxazole (XIII).

Desired disubstituted thiazoles, which may be used as R₈ in Scheme III and IV (Method C and D) may be prepared by the Hantzsch method in which a thioamide is condensed with an alpha-halocarbonyl compound. This method is known to those skilled in the art and is well-documented in the chemical literature (for example, J. Metzger and E. J. Vincent, The Chemistry of Heterocyclic Compounds, Vol. 34, 1979; A. R. Katritzky et al., J. Org. Chem., 1995, 60, 5638; R. Flaig and H. Hartmann, Heterocycles, 1997, 45, 875).

Methods of Therapeutic Use

The compounds of this invention effectively block degradation of the invariant chain to CLIP by cathepsin S, and thus inhibit antigen presentation and antigen-specific immune responses. Control of antigen specific immune responses is an attractive means for treating autoimmune diseases and other undesirable T-cell mediated immune responses. Thus, there is provided methods of treatment using the compounds of this invention for such conditions. These encompass autoimmune diseases including, but not limited to, rheumatoid arthritis, systemic lupus erythematosus, Crohn's disease, ulcerative colitis, multiple sclerosis, Guillain-Barre syndrome, psoriasis, Grave's disease, myasthenia gravis, scleroderma, glomerulonephritis, atopic dermatitis and insulin-dependent diabetes mellitus. The compounds of the invention can also be used to treat other disorders associated with extracellular proteolysis such as Alzheimer's disease. The compounds of the invention can also be used to treat other disorders associated with inappropriate autoimmune responses, T-cell mediated immune responses, or extracellular proteolysis mediated by cathepsin S, unrelated to those listed above or discussed in the Background of the Invention. Therefore, the invention also provides methods of modulating an autoimmune disease comprising administering to a patient in need of such treatment a pharmaceutically effect amount of a compound according to the invention.

For therapeutic use, the compounds of the invention may be administered in any conventional dosage form in any conventional manner. Routes of administration include, but are not limited to, intravenously, intramuscularly, subcutaneously, intrasynovially, by infusion, sublingually, transdermally, orally, topically or by inhalation. The preferred modes of administration are oral and intravenous.

The compounds of this invention may be administered alone or in combination with adjuvants that enhance stability of the inhibitors, facilitate administration of pharmaceutical compositions containing them in certain embodiments, provide increased dissolution or dispersion, increase inhibitory activity, provide adjunct therapy, and the like, including other active ingredients. Advantageously, such combination therapies utilize lower dosages of the conventional therapeutics, thus avoiding possible toxicity and adverse side effects incurred when those agents are used as monotherapies. Compounds of the invention may be physically combined with the conventional therapeutics or other adjuvants into a single pharmaceutical composition. Advantageously, the compounds may then be administered together in a single dosage form. In some embodiments, the pharmaceutical compositions comprising such combinations of compounds contain at least about 15%, but more preferably at least about 20%, of a compound of formulas (I), (Ia), (II) or (IIa) (w/w) or a combination thereof. Alternatively, the compounds may be administered separately (either serially or in parallel). Separate dosing allows for greater flexibility in the dosing regime.

As mentioned above, dosage forms of the compounds of this invention include pharmaceutically acceptable carriers and adjuvants known to those of ordinary skill in the art. These carriers and adjuvants include, for example, ion exchangers, alumina, aluminum stearate, lecithin, serum proteins, buffer substances, water, salts or electrolytes and cellulose-based substances. Preferred dosage forms include, tablet, capsule, caplet, liquid, solution, suspension, emulsion, lozenges, syrup, reconstitutable powder, granule, suppository and transdermal patch. Methods for preparing such dosage forms are known (see, for example, H. C. Ansel and N. G. Popovish, Pharmaceutical Dosage Forms and Drug Delivery Systems, 5th ed., Lea and Febiger (1990)). Dosage levels and requirements are well-recognized in the art and may be selected by those of ordinary skill in the art from available methods and techniques suitable for a particular patient. In some embodiments dosage levels range from about 10-1000 mg/dose for a 70 kg patient. Although one dose per day may be sufficient, up to 5 doses per day may be given. For oral doses, up to 2000 mg/day may be required. As the skilled artisan will appreciate, lower or higher doses may be required depending on particular factors. For instance, specific dosage and treatment regimens will depend on factors such as the patient's general health profile, the severity and course of the patient's disorder or disposition thereto, and the judgment of the treating physician.

SYNTHETIC EXAMPLES Example 1 Morpholine-4-carboxylic acid [1-(S)-(1-(S)-cyano-3-phenylpropylcarbamoyl)-3-methylbutyl]amide

As outlined generally in Scheme I (Method A), N-Boc-L-homophenylalanine (0.50 g, 1.79 mmol) was dissolved in 20 mL of DMF which was cooled with an ice-water bath. 1-Hydroxybenzotriazole (HOBT) (0.29 g, 2.14 mmol) and EDC (0.41 g, 2.00 mmol) were added followed by stirring for 20 min. Ammonium hydroxide was added (0.5 mL) and stirring was continued overnight (16 h). The reaction mixture was diluted with 50 mL of methylene chloride to give a white precipitate. The mixture was filtered and the filtrate was washed with brine (100 mL) followed by saturated bicarbonate (100 mL). The organic layer was dried over MgSO₄, filtered and concentrated by rotary evaporation to give the corresponding amide (0.45 g, 90%) that was used without further purification.

Benzyl L-leucine p-toluenesulfonate salt (8.00 g, 20.3 mmol) was dissolved in 20 mL of DMF followed by addition of N,N-diisopropylethylamine (10.61 mL, 60.9 mmol) and stirring under Ar for 15 min. 4-Morpholinecarbonyl chloride (4.55 g, 30.4 mmol) was added and stirring was continued overnight (16 h). The solution was diluted with 500 mL of EtOAc and washed with 3×500 mL of water. The organic layer was dried over MgSO₄, filtered and concentrated by rotary evaporation to 8.01 g of the crude product. The product was purified by flash chromatography (SiO₂, 40% EtOAc/hexane) resulting in a thick oil. This oil (18 g, 53.8 mmol) was dissolved in ethanol (500 mL). Pd(OH)₂ (642 mg) was added followed by cyclohexene (100 mL). The mixture was refluxed for 45 min at which time TLC indicated consumption of the benzyl ester. The reaction was cooled and filtered through diatomaceous earth and evaporated to dryness to give N-(4-morpholinecarbonyl)-L-leucine as a very thick oil (13 g 99%) that was used without further purification.

N-Boc-L-homophenylalaninamide (from the first paragraph) (114 mg, 0.41 mmol) was dissolved in 10 mL of CH₂Cl₂ and 10 mL of trifluoroacetic acid (TFA) was added. Stirring was continued for 30 min at which time the reaction mixture was evaporated to dryness giving the TFA salt of L-homophenylalanine amide. N-(4-morpholinecarbonyl)-L-leucine (100 mg, 0.41 mmol), from above, was dissolved in 10 mL of DMF and cooled by an ice-water bath. HOBT (72 mg, 0.53 mmol) and EDC (102 mg, 0.53 mmol) were added and the mixture was stirred at 0° C. for 15 min. To the cold solution was added the TFA salt of L-homophenylalaninamide as a solution in 5 mL of DMF, followed by addition of N-methylmorpholine (94 μL, 0.86 mmol). The ice bath was removed and the reaction was stirred at ambient temperature overnight (16 h). The reaction was diluted with 50 mL of CH₂C₂ to give a white precipitate. The mixture was filtered and the solid washed with an additional 50 mL of CH₂Cl₂. The filtrates were combined and washed with saturated bicarbonate (100 mL), 1 N HCl (100 mL) and brine (2×100 mL). The organic layer was dried over MgSO₄ and concentrated by rotary evaporation to give an oily residue. The residue was chromatographed (SiO₂, 5% MeOH in CH₂Cl₂) to give the a white solid (130 mg, 78%).

This amide (150 mg, 0.37 mmol) (material from more than one reaction) was dissolved in 2 mL of DMF and cooled to 0° C. with an ice-water bath. To the solution was added cyanuric chloride (46 mg, 0.37 mmol). The ice bath was removed and the reaction stirred to ambient temperature over the next hour. During the course of the reaction a white precipitate formed. The reaction was diluted with 100 ml of EtOAc and washed with 100 ml of water (3×). The organic layer was dried over MgSO₄, filtered and concentrated by rotary evaporation to give the crude residue. The residue was purified by chromatography (SiO₂, 40% hexane in EtOAc) to give the title compound as a hard white glass (120 mg, 84%). ¹H NMR (270 MHz, CDCl₃): δ8.00-7.87 (1H, m), 7.35-7.13 (3H, m), 712-7.05 (2H, m), 5.10-5.02 (1H, m), 4.80-4.60 (1H, m), 4.45-4.20 (1H, m), 3.75-3.50 (4H, m), 3.45-3.30 (4H, m), 2.80-2.60 (2H, m), 2.10-1.90 (2H, m), 1.70-1.45 (3H, m), 1.05-0.90 (6H, m).

Example 2 2-(S)-(4-Dimethylaminobenzenesulfonylamino)-4-methylpentanoic acid (1-(S)-cyano-3-phenylpropyl) amide

NH₄OH (4 mL) was added to a premixed (15 min) solution of N-(t-butoxycarbonyl)-L-homophenylalanine (4.00 g, 14.3 mmol), EDC (3.24 g, 17.2 mmol). and HOBT (2.32 g, 17.2 mmol) in DMF (20 mL) at room temperature. After 16 h the reaction mixture was diluted with CH₂Cl₂ and filtered, washed sequentially with 10% aqueous HCl, satd. NaHCO₃, H₂O (×3), brine, dried over Na₂SO₄, and concentrated giving N-(t-butoxycarbonyl)-L-homophenylalaninamide (3.10 g, 78%) as a white solid.

TFA (2.5 mL) was added to a solution of N-(t-butoxycarbonyl)-L-homophenylalaninamide (1.00 g, 3.59 mmol) in CH₂Cl₂ (10 mL) at room temperature. After stirring for 0.5 h the reaction mixture was concentrated giving a colorless oil. As described generally by Scheme II, Method B, the oil was dissolved in CH₂Cl₂ (10 mL) and N,N-diisopropylethylamine (1.90 g, 14.4 mmol) and added to a premixed (15 min) solution of N-(t-butoxycarbonyl)-L-leucine (913 mg, 3.95 mmol). EDC (826 mg, 4.30 mmol), HOBT (581 mg, 4.30 mmol) in CH₂Cl₂ (10 mL) at room temperature. After stirring for 16 h the reaction was quenched by the addition of H₂O, diluted with EtOAc, washed sequentially with 10% aqueous HCl, satd. NaHCO₃, H₂O brine, dried over Na₂SO₄, and concentrated giving 1.3 g of a white solid. The crude solid was triturated with 5% EtOAc/Hexane giving N-[N-(t-butoxycarbonyl)-L-leucinyl]-L-homophenylalaninamide (1.1 g, 78%) as a white solid.

TFA (2.5 mL) was added to a solution of N-[N-(t-butoxycarbonyl)-L-leucinyl]-L-homophenylalaninamide (500 mg, 1.28 mmol) in CH₂Cl₂ (10 mL) at room temperature. After stirring for 0.5 h the reaction mixture was concentrated giving a colorless oil which was diluted with CH₂Cl₂ (2.5 ml). Diisopropylethylamine (588 mg, 4.55 mmol) and p-Me₂NC₆H₄SO₂Cl [prepared by the reaction of p-Me₂NC₆H₄SO₃ ⁻Na⁺ (1.0 g, 4.48 mmol) with thionyl chloride and pyridine (1 mL) at 55° C. for 2 h followed by cooling, diluting with toluene and concentrating to give p-Me₂NC₆H₄SO₂Cl.] was added at room temperature. After stirring for 16 h the reaction was quenched by the addition of H₂O, diluted with EtOAc, washed sequentially with 10% aqueous HCl, satd. NaHCO₃, H₂O (×3), brine, dried over Na₂SO₄, and concentrated giving a yellow solid (408 mg). The crude residue was fractionated by flash chromatography (25-100% EtOAc/Hexane) giving N-[N-((4-dimethylaminophenyl)sulfonyl)-L-leucinyl]-L-homophenylalaninamide (90 mg, 15%) as a white solid. Some title compound (60 mg, 10%) was isolated from this reaction as well.

Cyanuric chloride (33 mg, 0.18 mmol) was added to a solution of N-[N-((4-dimethylaminophenyl)sulfonyl)-L-leucinyl]-L-homophenylalaninamide (80 mg, 0.18 mmol) in DMF (2 mL) at 0° C. After stirring for 2h, the reaction was quenched by addition of satd. NaHCO₃, filtered, diluted with EtOAc, washed sequentially with H₂O (×5), brine, dried over Na₂SO₄, and concentrated giving a yellow foam. The crude residue was fractionated by preparative HPLC (65% AcCN/H₂O/0.1% TFA) giving the title compound (47 mg, 57%) as a white solid, m.p. 46-48° C. ¹H NMR (400 MHz, CDCl₃): δ: 7.74(2H, d, J=9), 7.37-7.34 (2H, m), 7.30-7.26 (2H, m), 7.23-7.21 (3H, m), 6.79 (1H, d, J=8.5), 4.91 (1H, bs), 4.70 (1H, ddd, J=8, 8, 8), 3.68-3.73 (1H, m), 3.06 (3H, s), 2.84-2.76 (2H, m), 2.16-2.09(2H, m), 1.63-1.56 (2H, m), 1.42-1.37 (1H, m), 0.88 (3H, d, J=6), 0.71 (3H, d, J=6).

Example 3 2-(2-(S)-{4-Methyl-2-(S)-[(morpholine-4-carbonyl)amino]pentanoylamino}-4-phenylbutyryl)benzothiazole-6-carboxylic acid phenylamide

As described generally in Method C, N-(t-Boc)-L-homophenylalanine (10.0 g, 35.8 mmol) was dissolved in 50 mL of DMF. The solution was cooled to 0° C. with an ice-water bath. Carbonyldiimidazole (6.4 g, 39.4 mmol) was added to the reaction solution followed by N-methylmorpholine (3.9 g, 39.4 mmol). The reaction was stirred for 1 h at which time N,O-dimethylhydroxylamine hydrochloride (3.8 g, 39.4 mmol) was added. The ice bath was removed and the reaction was stirred at ambient temperature for 3 h. The reaction solution was poured into 200 mL of 1N HCl and extracted with 200 mL of EtOAc. The organic layer was washed with 2×100 mL of 1N HCl, 100 mL of saturated sodium bicarbonate, 2×100 mL water, and 2×100 mL brine. The organic layer was dried over Na₂SO₄, decanted and concentrated by rotary evaporation to give the desired amide as a thick oil (11.1 g, 96% crude) which was used without further purification.

The amide (3.7 g, 11.5 mmol), dissolved in 20 mL THF was added dropwise over 20 min to a suspension of LiAlH₄ (0.53 g, 13.9 mmol) in 60 mL THF which was cooled to 0° C. in an ice-water bath. The mixture was stirred for 15 min, then quenched with 10 mL of a saturated solution of sodium bicarbonate, diluted with 200 mL water and extracted with 3×100 mL EtOAc. The organic layers were combined and washed with 100 mL 1 N HCl and 2×100 mL brine. The organic layer was dried over Na₂SO₄, filtered over a pad of diatomaceous earth and concentrated by rotary evaporation. The residue was purified by flash chromatography (SiO₂, 5% i-PrOH in CH₂Cl₂) to give the desired aldehyde as an oily solid (2.4 g, 79%).

To a dry 100 mL flask was added 6-(phenylcarbamoyl)benzothiazole (0.58 g, 2.3 mmol) and THF (12 mL). The reaction mixture was cooled to −78° C. with a dry-ice/acetone bath. n-BuLi (2.5 M in hexanes) (1.8 mL, 4.5 mmol) was added dropwise to the reaction mixture. The reaction was stirred for 20 min to give a suspension. A solution of the above aldehyde (200 mg, 0.75 mmol) in 3 mL of dry THF was added all at once via syringe. The temperature was gradually increased to −40° C. and the reaction was stirred for 3 h at which time TLC showed consumption of the aldehyde. The reaction was quenched at −78° C. by the addition of a saturated solution of NH₄Cl and the product was extracted with 50 mL EtOAc. The organic layer was dried over MgSO₄, filtered and concentrated to give a residue that was purified by chromatography (SiO₂, 2% MeOH in CH₂Cl₂) to give the desired alcohol as a solid (194 mg, 50%).

N-(4-morpholinecarbonyl)-L-leucine (26.4 mg, 0.11 mmol) (prepared as described in Example 1) was dissolved in 2 mL of DMF. The solution was cooled to 0° C. with an ice-water bath and HOBT (19 mg, 0.14 mmol) and EDC (27 mg, 0.14 mmol) were added and the solution stirred for 20 min. The TFA salt of the N-deprotected alcohol from above (prepared by stirring the above N-Boc protected alcohol in methylene chloride with TFA at room temperature for 30 min and evaporation to dryness) (57 mg, 0.11 mmol of N-Boc precursor) was added to the reaction as a solution in 1 mL of DMF followed by addition of N-methylmorpholine (35 μL, 0.32 mmol). The reaction was stirred for 3 h, diluted with EtOAc and washed with 10 mL 1N HCl and 10 mL saturated bicarbonate and 2×100 mL brine. The organic layer was dried over MgSO₄, filtered and concentrated. The residue was purified by chromatography (SiO₂, 2% MeOH in CH₂Cl₂) to give the desired coupled product as a white solid (57 mg, 82%).

To the above product (50.4 mg, 0.08 mmol) was added the Dess-Martin periodinane (133 mg, 0.31 mmol), 10 mL CH₂Cl₂ and 4 mL t-BuOH. The reaction mixture was allowed to stir overnight at room temperature. It was then was diluted with 20 mL CH₂Cl₂, washed with 20 mL of saturated solution of Na₂S₂O₃ and 20 mL NaHCO₃ solution the organic layer was washed with brine, dried over MgSO₄, filtered and concentrated. The residue was purified by chromatography (SiO₂, 2% MeOH in CH₂Cl₂) to give the title compound as a white solid (30 mg, 60%), ¹H NMR (270 MHz, CDCl₃): δ8.77-8.70 (1H, m), 8.57-8.52 (1H, m), 8.28-8.20 (1H, m), 8.15-8.07 (1H, m), 7.78-7.68 (2H, m), 7.45-7.35 (2H, m), 7.29-7.05 (7H, m), 5.75-5.65 (1H, m), 5.00-4.92 (1H, m), 4.54-4.41 (1H, m), 3.74-3.58 (4H, m), 3.40-3.24 (4H, m), 2.78-2.62 (2H, m), 2.51-2.32 (1H, m), 2.21-2.02 (1H, m), 1.90-1.40 (3H, m), 1.00-0.80 (6H, m).

Example 4 Morpholine-4-carboxylic acid {1 -(S)-[1-(S)-(benzothiazole-2-carbonyl)-3-phenylpropylcarbamoyl]-3-methylbutyl}amide

Dry THF (1.5 mL), under Ar, was cooled to −78° C. with a dry-ice/acetone bath. n-BuLi (2.0 M in hexanes) (698 μL, 1.40 mmol) was added to reaction flask followed by dropwise addition of freshly distilled benzothiazole (180 mg, 1.40 mmol) as a solution in 0.5 mL of dry THF. The reaction was stirred for 15 min to give a suspension. A solution of N-(t-butoxycarbonyl)-(N′-methyl-N′-methoxy)-L-homophenylalaninamide (300 mg, 0.930 mmol) (prepared as described in Example 3) in 1 mL of dry THF was added all at once via syringe. The reaction was stirred for 5 min at which time TLC showed consumption of the amide. The reaction was quenched by the addition of water and the product extracted with 50 mL of EtOAc. The organic layer was dried over MgSO₄, filtered and concentrated to give a residue that was purified by preparative TLC (CH₂Cl₂) to give the desired ketone as a clear colorless oil.

N-(4-morpholinecarbonyl)-L-leucine (82 mg, 0.34 mmol) (prepared as described in Example 1) was dissolved in 2 mL of DMF. The solution was cooled to ⁰° C. with an ice-water bath and HOBT (60 mg, 0.44 mmol) and EDC (83 mg, 0.44 mmol) were added and the solution stirred for 20 min. The TFA salt of the N-deprotected ketone from above (prepared by stirring the above N-Boc protected alcohol in methylene chloride with TFA at room temperature for 30 min and evaporation to dryness) (133 mg, 0.34 mmol of N-Boc precursor) was added to the reaction as a solution in 1 mL of DMF followed by addition of N-methylmorpholine (77 μL, 0.70 mmol). The reaction was stirred for 3 h, diluted with EtOAc and washed with 100 mL 1N HCl and 100 mL saturated bicarbonate and 2×100 mL brine. The organic layer was dried over MgSO₄, filtered and concentrated. The residue was purified by chromatography (SiO₂, 50% EtOAc in hexane) to give the title compound as a white solid (40 mg, 23%) that was shown to be a 1 to 1 mixture of two epimers. ¹H NMR (270 MHz, CDCl₃): δ8.15-8.08 (1H, m), 7.98-7.88 (1H, m), 7.60-7.40 (2H, m), 7.25-7.07 (5H, m), 7.02-6.92 (1H, m), 5.90-5.75 (1H, m), 4.98-4.90 (1H, m), 4.50-4.35 (1H, m), 3.66-3.57 (4H, m), 3.40-3.30 (4H, m), 2.80-2.70 (2H, m), 2.50-2.35 (1H, m), 2.25-2.10 (1H, m), 1.80-1.40 (3H, m), 1.00-0.88 (6H, m).

Example 5 Morpholine-4-carboxylic acid {1-(S)-[1-(S)-(2,4-diphenyloxazole-5-carbonyl)-3-phenylpropylcarbamoyl]-3-methylbutyl}amide

As outlined generally in Scheme IV (Method D), 2,4-diphenyloxazole (361 mg, 1.63 mmol) in 15 mL dry THF was cooled to −78° C. and n-butyllithium (1.16 ml of a 1.4 M solution, 1.63 mmol) was added. After stirring for 1 h at −78° C., a solution of the free base of N-[N-(t-butoxycarbonyl)-L-leucinyl]-L-homophenylalaninamide (prepared as described in Example 3) in 5 mL of dry THF was added dropwise. The temperature of the reaction mixture was allowed to rise to −20° C. and maintained for 2 h after which time the reaction mixture was quenched with 100 mL of NH₄Cl (10% aqueous) and extracted with 3×100 mL EtOAc. The combined extracts were washed with 2×100 mL brine, dried with Na2SO₄, filtered and concentrated. The resulting residue was purified by chromatography (florisil, 15% -20% hexane in EtOAc) yielding 190 mg (72%) of [1-(2,4-diphenyloxazole-5-carbonyl)-3-phenylpropyl]carbamic acid tert-butyl ester.

N-[(4-Morpholinyl)carbonyl]-L-leucine (100 mg, 0.35 mmol) (prepared as described in Example 1) was dissolved in 10 mL DMF and cooled to 0° C. To the solution was added EDC (77 mg, 0.4 mmol) and HOBt (54 mg, 0.4 mmol) and the reaction was stirred for 1 h. In a separate flask, [1-(2,4-diphenyloxazole-5-carbonyl)-3-phenylpropyl]carbamic acid tert-butyl ester (158 mg, 0.31 mmol) was dissolved in 4 mL CH₂Cl₂ and 2 mL TFA was added. After stirring for 1 h, the solvents were evaporated, the residue was dissolved in 5 mL DMF and N-methylmorpholine (406 mg, 0.4 mmol) was added. The resulting solution was added to the previously prepared solution of activated leucine derivative at 0° C. The reaction mixture was stirred at room temperature for 3 h, cooled to 0° C., and quenched with 100 ml of a 10% solution of citric acid in water. The resulting mixture was extracted with 3×100 mL EtOAc. The combined organic extracts were washed with 2×100 mL of saturated bicarbonate and 1×100 mL brine. The organic layer was dried over Na₂SO₄, filtered and concentrated to a residue that was purified by chromatography (florisil, 30%-50% EtOAc in hexane) to give the title compound as a white solid (90mg, 84%) m.p. 83-5° C., MS (ES) 609 (M⁺).

The following compounds were also prepared using the procedure described in Example 5:

Morpholine-4-carboxylic acid {1-(S)-[1S-(2,4-diphenyl-oxazol-5-carbonyl)-3-phenyl-propylcarbamoyl]-3,3-dimethylbutyl}amide, m.p. 95-7° C., MS (ES) 623 (M⁺).

Morpholine-4-carboxylic acid {2-cyclohexyl-1-(S)-[1-(S)-(2,4-diphenyl-oxazole-5-carbonyl)-3-phenyl-propylcarbamoyl]-ethyl}amide, m.p. 93-5° C., MS (ES) 649 (M⁺).

Morpholine-4-carboxylic acid {1-(S) -[2,4-diphenyl-oxazole-5-yl)-2-oxo-ethylcarbamoyl]-3-methylbutyl}amide, m.p. 155-7° C., MS (ES) 505 (M⁺).

Morpholine-4-carboxylic acid {2-cyclohexyl-1-(S)-[2-(2,4-diphenyl-oxazol-5-yl)-2-oxo-ethylcarbamoyl]-ethyl}-amide, m.p. 122-3° C., MS (ES) 545 (M⁺).

Morpholine-4-carboxylic acid {1-(S)-[2-(2,4-diphenyl-oxazol-5-yl)-2-oxo-ethylcarbamoyl]-3,3-dimethylbutyl}-amide, m.p. 97-9° C., MS (ES) 519 (M⁺).

Morpholine-4-carboxylic acid (1-(S)-{1-(S)-[2-(3-benzyloxy-phenyl)-oxazole-5-carbonyl]-3-phenyl-propylcarbamoyl}-3-methyl-butyl)-amide, m.p. 61-3° C., MS (ES) 639 (M⁺).

Morpholine-4-carboxylic acid {2-cyclohexyl-1-(S)-[1-(R,S)-(4-isobutyl-2-pyrinin-2-yl-oxazole-5-carbonyl)-3-phenyl-propylcarbamoyl]-ethyl}amide, m.p. 93-5° C., MS (ES) 649 (M⁺).

Example 6 2-(4-Isobutyloxazol-2-yl)pyridine (Method E)

N-(t-Butoxy)-L-leucine (10 g, 43 mmol) was dissolved in 200 mL of CH₂Cl₂. The solution was cooled to 0° C. with an ice-water bath. Carbonyldiimidazole (7.7 g, 47.5 mmol) was added and the reaction mixture was stirred for 1 h. N-O-dimethylhydroxylamine hydrochloride (4.64 g, 47.8 mmol) was added at 0° C. The ice bath was removed and the reaction was stirred at ambient temperature for 16 h. The reaction solution was poured into 200 mL of an ice-cooled solution of 5% citric acid. The organic layer was separated, washed with 2×100 mL of 1N HCl, 1×100 mL of saturated NaHCO₃, and 2×100 mL brine. The organic layer was dried over Na₂SO₄, filtered, and concentrated by rotary evaporation to five [1-(N-methoxy-N-methylcarbamoyl)-3-methylbutyl]carbamic acid tert-butyl ester as a thick oil (7.39 g, 59% crude) which was used without further purification.

The tert-butyl ester from above (1 g, 3.47 mmol) was dissolved in 10 mL CH₂Cl₂ and 5 mL trifluoroacetic acid was added. The reaction mixture was stirred for 1 h. Solvents were evaporated and the residue was taken up in 2×10 mL CH₂Cl₂ and evaporated to an oil. In a separate flask, picolinic acid (470 mg, 3.82 mmol) was dissolved in 10 mL DMF and the resulting solution was cooled to 0° C. EDC (787 mg, 4.1 mmol) and HOBT (554 mg, 4.1 mmol) were added and the reaction mixture was stirred at 0° C. for 1 h. In a separate flask, the free amine prepared above was dissolved in 5 mL DMF and 1.5 mL N-methylmorpholine was added. This solution was added to the reaction mixture at 0° C. The reaction mixture was allowed to stir at ambient temperature for 16 h after which time it was poured into a mixture of ice/5% citric acid (100 mL) and extracted with 4×30 mL EtOAc. The combined EtOAc extracts were washed with 3×100 mL brine. 2×100 mL NaHCO₃. 1×100 mL brine, dried with Na₂SO₄, and evaporated to an oil which was dried under vacuum yielding 990 mg (100%) of pyridine-2-carboxylic acid [1-(N-methoxy-N-methylcarbamoyl)-3-methylbutyl]amide. This was used without further purification.

The amide from above (4.7 g, 14.7 mmol) was dissolved in 50 mL THF and added to a slurry of LiAlH₄ (558 mg, 14.7 mmol) in 50 mL THF at −78° C. The reaction mixture was allowed to warm to 0° C. and maintained for 15 min, after which time it was cooled to −78° C. and cannulated into an ice-cooled solution of KHSO₄ (8.16 g, 60 mmol) in 200 mL H₂O. The resulting mixture was extracted with 5×100 mL EtOAc. The combined extracts were washed with 2×100 mL satd.NaHCO₃ and 1×100 mL brine, dried with Na₂SO₄ and evaporated to an oily residue which was flash chromatographed through SiO₂ (25% EtOAc/hexane—35% EtOAc/hexane) yielding 2.8 g (86%) of pyridine-2-carboxylic acid (1-formyl-3-methylbutyl)amide as a colorless oil which solidified on standing.

Hexachloroethane (445 mg, 1.87 mmol) was dissolved in 5 mL CH₃CN. A solution of pyridine-2-carboxylic acid (1-formyl-3-methylbutyl)amide (137.5 mg, 0.625 mmol) in 2 mL CH₃CN was added followed by triethylamine (375 mg, 3.75 mmol) and triphenylphosphine (491 mg, 1.87 mmol). The resulting mixture was stirred for ½ h, poured into brine, and extracted with 2×25 mL EtOAc. The combined extracts were washed with 1×50 mL brine, dried with Na₂SO₄ and evaporated to 665 mg of a tan solid which was flash chromatographed through SiO₂ (20%-35% hexane/EtOAc) yielding 100 mg (76%) of the title compound as an amber oil, MS (ES) 203 (M⁺).

Assessment of Biological Properties

Expression and Purification of Recombinant Human Cathepsin S

Cloning of Human Cathepsin S

U937 RNA was subjected to reverse transcriptase/polymerase chain reaction with primer A (5′cacaatgaaacggctggtttg 3′) and primer B (5′ctagatttctgggtaagaggg 3′) designed to specifically amplify the cathepsin S cDNA. The resulting 900 bp DNA fragment was subcloned into pGEM-T (Promega) and sequenced to confirm its identity. This construct was used for all subsequent manipulations. This procedure is typical for cloning of known genes and is established in its field.

Human Pre-Pro-Cat S was removed from pGem-T vector (Promega. 2800 Woods Hollow Rd, Madison, Wis. 53711) by digestion with restriction enzyme SacII, followed by treatment with T4 DNA polymerase to generate a blunt end, and a second restriction enzyme digest with SalI. It was subcloned into pFastBac1 donor plasmid (GibcoBRL, 8717 Grovemont Cr., Gaithersburg, Md. 20884) which had been cut with restriction enzyme BamH1 and blunt-ended and then cut with restriction enzyme SalI. The ligation mixture was used to transform DH5a competent cells (GibcoBRL) and plated on LB plates containing 100 ug/ml ampicillin. Colonies were grown in overnight cultures of LB media containing 50 ug/ml Ampicillin, plasmid DNA isolated and correct insert confirmed by restriction enzyme digestion. Recombinant pFastBac donor plasmid was transformed into DH10Bac competent cells (GibcoBRL). Large white colonies were picked from LB plates containing 50 ug/ml kanamycin, 7 ug/ml gentamicin, 10 ug/ml tetracycline, 100 ug/ml Bluo-gal, and 40 ug/ml IPTG. DNA was isolated and used to transfect Sf9 insect cells using CellFECTIN reagent (GibcoBRL). Cells and supernatant were harvested after 72 hours. Viral supernatant was passaged twice and presence of Cat S confirmed by PCR of the supernatant. SF9 cells were infected with recombinant baculovirus at a MOI of 5 for 48-72 hrs. Cell pellet was lysed and incubated in buffer at pH 4.5 at 37 for 2 hours to activate Cat S from pro-form to active mature form (Bromme, D & McGrath, M., Protein Science. 1996, 5:789-791.) Presence of Cat S was confirmed by SDS-PAGE and Western blot using rabbit anti-human proCat S.

Inhibition of Cathepsin S

Human recombinant cathepsin S expressed in Baculovirus is used at a final concentration of 10 nM in buffer. Buffer is 50 mM Na Acetate, pH 6.5, 2.5 mMEDTA, 2.5 mMTCEP. Enzyme is incubated with either compound or DMSO for 10 min at 37 C. Substrate 7-amino-4-methylcoumarin, CBZ-L-valyl-L-valyl-L-arginineamide (custom synthesis by Molecular Probes) is diluted to 20 uM in water (final concentration of 5 uM), added to assay and incubated for additional 10 minutes at 37 C. Compound activity is measured by diminished fluorescence compared to DMSO control when read at 360 nm excitation and 460 nm emission.

Examples listed above were evaluated for inhibition of cathepsin S in the above assay. All had IC₅₀ of 100 micromolar or below.

The following prophetic compounds may be made in accordance with the procedure outlined in Scheme IV (Method D), and the specific example 5:

Morpholine-4-carboxylic acid {1-[2-(4-isobutyl-2-pyridin-2-yl-oxazol-5-yl)-2-oxo-ethylcarbamoyl]-3-methyl-butyl}-amide;

Morpholine-4-carboxylic acid {1-[2-(4-cyclohexylmethyl-2-pyridin-2-yl-oxazol-5-yl)-2-oxo-ethylcarbamoyl]-3-methyl-butyl}-amide;

Morpholine-4-carboxylic acid {1-[2-(4-cyclohexylmethyl-2-pyridin-3-yl-oxazol-5-yl)-2-oxo-ethylcarbamoyl]-3-methyl-butyl}-amide;

Morpholine-4-carboxylic acid {2-cyclohexyl-1-[2-(4-cyclohexylmethyl-2-pyridin-3-yl-oxazol-5-yl)-2-oxo-ethylcarbamoyl]-ethyl}-amide;

Morpholine-4-carboxylic acid {2-cyclohexyl-1-[2-(4-isobutyl-2-pyridin-3-yl-oxazol-5-yl)-2-oxo-ethylcarbamoyl]-ethyl}-amide;

Morpholine-4-carboxylic acid {1-[2-(4-isobutyl-2-pyridin-3-yl-oxazol-5-yl)-2-oxo-ethylcarbamoyl]-3-methyl-butyl}-amide;

Morpholine-4-carboxylic acid {1-[1-(4-isobutyl-2-pyridin-3-yl-oxazole-5-carbonyl)-3-phenyl-propylcarbamoyl]-3-methyl-butyl}-amide;

Morpholine-4-carboxylic acid {1-[1-(4-isobutyl-2-pyridin-3-yl-oxazole-5-carbonyl)-3-phenyl-propylcarbamoyl]-3,3-dimethyl-butyl}-amide;

Morpholine-4-carboxylic acid {1-[1-(4-isobutyl-2-pyridin-4-yl-oxazole-5-carbonyl)-3-phenyl-propylcarbamoyl]-3,3-dimethyl-butyl}-amide;

Morpholine-4-carboxylic acid {2-cyclohexyl-1-[1-(4-isobutyl-2-pyridin-4-yl-oxazole-5-carbonyl)-3-phenyl-propylcarbamoyl]-ethyl}-amide;

Morpholine-4-carboxylic acid {2-cyclohexyl-1-[1-(4-cyclohexylmethyl-2-pyridin-4-yl-oxazole-5-carbonyl)-3-phenyl-propylcarbamoyl]-ethyl}-amide;

Morpholine-4-carboxylic acid (2-cyclohexyl-1-{1-[4-isobutyl-2-(1-methyl-piperidin-4-yl)-oxazole-5-carbonyl]-3-phenyl-propylcarbamoyl}-ethyl)-amide;

Morpholine-4-carboxylic acid (1-{1-[4-isobutyl-2-(1-methyl-piperidin-4-yl)-oxazole-5-carbonyl]-3-phenyl-propylcarbamoyl}-3,3-dimethyl-butyl)-amide;

Morpholine-4-carboxylic acid (1-{1-[4-isobutyl-2-(1-pyrimidin-2-yl-piperidin-4-yl)-oxazole-5-carbonyl]-3-phenyl-propylcarbamoyl}-3,3-dimethyl-butyl)-amide;

Morpholine-4-carboxylic acid (1-{2-[4-isobutyl-2-(1-pyrimidin-2-yl-piperidin-4-yl)-oxazol-5-yl]-2-oxo-ethylcarbamoyl}-3,3-dimethyl-butyl)-amide;

Morpholine-4-carboxylic acid (1-{2-[4-cyclohexylmethyl-2-(1-pyrimidin-2-yl-piperidin-4-yl)-oxazol-5-yl]-2-oxo-ethylcarbamoyl}-3-)methyl-butyl)-amide;

Morpholine-4-carboxylic acid {1-[2-(4-cyclohexylmethyl-2-piperidin-3-yl-oxazol-5-yl)-2-oxo-ethylcarbamoyl]-3-methyl-butyl}-amide;

Morpholine-4-carboxylic acid {1-[2-(4-isobutyl-2-piperidin-3-yl-oxazol-5-yl)-2-oxo-ethylcarbamoyl]-3-methyl-butyl}-amide;

Morpholine-4-carboxylic acid (1-{2-[4-isobutyl-2-(1-methyl-piperidin-3-yl)-oxazol-5-yl]-2-oxo-ethylcarbamoyl}-3-methyl-butyl)-amide.

Morpholine-4-carboxylic acid (1-{2-[4-isobutyl-2-(1-methyl-piperidin-3-yl)-oxazol-5-yl]-2-oxo-ethylcarbamoyl}-3,3 -dimethyl-butyl)-amide;

Morpholine-4-carboxylic acid (1-{2-[4-isobutyl-2-(1-methyl-piperidin-2-yl)-oxazol-5-yl]-2-oxo-ethylcarbamoyl}-3,3 -dimethyl-butyl)-amide;

Morpholine-4-carboxylic acid (1-{1-[4-isobutyl-2-(1-methyl-piperidin-2-yl)-oxazole-5-carbonyl]-3-phenyl-propylcarbamoyl}-3-methyl-butyl)-amide;

Morpholine-4-carboxylic acid {1-[4-isobutyl-2-phenyl-oxazole-5-carbonyl)-3-phenyl-propylcarbamoyl]-3-methyl-butyl}-amide;

Morpholine-4-carboxylic acid {1-[1-(4-dimethylaminomethyl-2-phenyl-oxazole-5-carbonyl)-3-phenyl-propylcarbamoyl]-3-methyl-butyl}-amide;

Morpholine-4-carboxylic acid {1-[2-(4-dimethylaminomethyl-2-phenyl-oxazol-5-yl)-2-oxo-ethylcarbamoyl]-3-methyl-butyl}-amide;

Morpholine-4-carboxylic acid {2-cyclohexyl-1-[2-(4-dimethylaminomethyl-2-phenyl-oxazol-5-yl)-2-oxo-ethylcarbamoyl]-ethyl}-amide;

Morpholine-4-carboxylic acid {1-[2-(4-dimethylaminomethyl-2-phenyl-oxazol-5-yl)-2-oxo-ethylcarbamoyl]-3,3 -dimethyl-butyl}-amide;

Morpholine-4-carboxylic acid {1-[1-(4-dimethylaminomethyl-2-phenyl-oxazol-5-carbonyl)-3-phenyl-propylcarbamoyl]-3,3-dimethyl-butyl}-amide;

Morpholine-4-carboxylic acid {1-[1-(4-hydroxymethyl-2-phenyl-oxazol-5-carbonyl)-3-phenyl-propylcarbamoyl]-3,3-dimethyl-butyl}-amide;

Morpholine-4-carboxylic acid (3,3-dimethyl-1-{2-[4-(4-methyl-piperazin-1-ylmethyl)-2-phenyl-oxazol-5-yl]-2-oxo-ethylcarbamoyl}-butyl)-amide;

Morpholine-4-carboxylic acid (3,3-dimethyl-1-{2-[4-(4-methyl-piperazin-1-ylmethyl)-2-pyridin-4-yl-oxazol-5-yl]-2-oxo-ethylcarbamoyl}-butyl)-amide;

Morpholine-4-carboxylic acid (3-methyl-1-{1-[4-(4-methyl-piperazin-1-ylmethyl)-2-pyridin-4-yl-oxazole-5-carbonyl]-3-phenyl-propylcarbamoyl}-butyl)-amide;

{1-[4-Isobutyl-5-(2-{4-methyl-2-[(morpholine-4-carbonyl)-amino]-pentoylamino}-acetyl)-oxazol-2-yl]-3-methyl-butyl}carbamic acid benzyl ester;

Morpholine-4-carboxylic acid {2-cyclohexyl-1-[1-(4-isobutyl-2-pyrimidin-4-yl-oxazole-5-carbonyl)-3-phenyl-propylcarbamoyl]-ethyl}-amide:

Morpholine-4-carboxylic acid {2-cyclohexyl-1-[3-phenyl-1-(4-phenyl-2-pyridin-4-yl-thiazole-5-carbonyl)-propylcarbamoyl]-ethyl}-amide; and

Morpholine-4-carboxylic acid {2-cyclohexyl-1-[2-oxo-2-(2-pyridin-4-yl-4-p-tolyl-thiazole-5-yl)-ethylcarbamoyl]-ethyl}-amide.

Preferred prophetic compounds have S-stereochemistry at their asymmetric carbons. 

What is claimed is:
 1. A compound of the formula (II):

wherein: A is —C(Y)— or —SO₂— Y is O or S; R₁ is cycloalkyl, aryl, heterocyclyl or heteroaryl wherein R₁ is substituted or unsubstituted by one or more R_(b); R_(b) is selected from the group consisting of cycloalkyl, aryl, heterocyclyl, heteroaryl, alkoxy, aryloxy, alkanoyl, aroyl, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino; R_(b) is unsubstituted or substituted by one or more R_(c); R_(c) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, arylalkyl, alkoxy, aryloxy, arylalkoxy, alkanoyl, aroyl, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino; R₂ is H or alkyl; R₃ is H, alkyl, cycloalkyl, aryl, heterocyclyl or heteroaryl, wherein R₃ is unsubstituted or substituted by one or more R_(d); R_(d) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkoxy, aryloxy, arylalkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyl, aroyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(d) is unsubstituted or substituted by one or more R_(e); R_(e) is selected from the group consisting of alkyl, cycloalkyl, aryl, arylalkyl, alkoxy, aryloxy, arylalkoxy, alkanoyl, aroyl, amino, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino; R₄ is H or alkyl; R₅ is H or alkyl; R₆ is alkyl, cycloalkyl, aryl, heterocyclyl, aryl, heteroaryl or cyano, wherein R₆ is unsubstituted or substituted by one or more R_(f); R_(f) is selected from the group consisting of alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkoxy, aryloxy, arylalkoxy, alkanoyl, aroyl, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, aroyloxy, heteroarylalkoxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylcarbamoyl, arylcarbamoyl, alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylalkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(f) is unsubstituted or substituted by one or more R_(g); R_(g) is selected from the group consisting of alkyl, cycloalkyl, aryl unsubstituted or substituted by one or more groups selected from halogen, methyl or methoxy, heterocyclyl, heteroaryl, alkoxy, aryloxy, arylalkoxy, alkoxycarbonyl, aryloxycarbonyl, alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom unsubstituted or independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkanoylamino, aroylamino, alkylcarbamoyl, arylcarbamoyl, alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by alkyl, aryl, heterocyclyl or heteroaryl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by alkyl, aryl, heterocyclyl or heteroaryl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino; or R₅ together with R₆ form a 3 to 6 membered carbocyclic ring, the carbocyclic ring is unsubstituted or substituted with one or more R_(h); R_(h) is selected from the group consisting of alkyl, aryl, alkoxycarbonyl, aryloxycarbonyl, arylalkoxycarbonyl, carbamoyl wherein the nitrogen atom is unsubstituted or mono or di-substituted with a group selected from alkyl, cycloalkyl, aryl, arylalkyl, heterocyclyl, heteroaryl, halogen, hydroxy, carboxy and cyano; X is O, S or N—OH; or the pharmaceutically acceptable salts, esters, tautomers, individual isomers and mixtures of isomers thereof; with the proviso that when Y is O and R₆ is arylalkyl or heteroarylalkyl then R₁ cannot be cycloalkyl, aryl, heteroaryl, cycloalkyl-alkyl, aryl-alkyl or aryl-cycloalkyl.
 2. The compound according to claim 1 wherein: R₁ is C3-7cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl, indolinyl, pyranyl and thiopyranyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, wherein R₁ is unsubstituted or substituted by one or more R_(b); R_(b) is selected from the group consisting of C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, C1-8 alkoxycarbonyl, aryloxycarbonyl, C1-8 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkanoylamino, aroylamino, C1-8 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, pyrazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino; R_(b) is unsubstituted or substituted by one or more R_(c); R_(c) is selected from the group consisting of C1-8 alkyl, C3-6 cycloalkyl, aryl, C1-8 alkoxy, aryloxy, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino; R₃ is H, C1-8 alkyl, C3-7 cycloalkyl or aryl wherein R₃ is unsubstituted or substituted by one or more R_(d); R_(d) is selected from the group consisting of C1-8 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, alkanoyl, aroyl, C1-8 alkoxycarbonyl, aryloxycarbonyl, C1-8 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkanoylamino, aroylamino, C1-8 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(d) is unsubstituted or substituted by one or more R_(e); R_(e) is selected from the group consisting of C1-8 alkyl, C3-6 cycloalkyl, aryl, arylalkyl, C1-8 alkoxy, aryloxy, arylalkoxy, aroyl, amino, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino; R₆ is C1-8 alkyl, C3-7 cycloalkyl, aryl or cyano, wherein R₆ is unsubstituted or substituted by one or more R_(f); R_(f) is selected from the group consisting of C1-8 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, arylC1-8alkoxy, heteroarylC1-8alkoxy, C1-8 alkoxycarbonyl, aryloxycarbonyl, C1-8 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkanoylamino, aroylamino, C1-8 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylC1-8 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(f) is unsubstituted or substituted by one or more R_(g); R_(g) is selected from the group consisting of C1-8 alkyl, C3-7 cycloalkyl, aryl unsubstituted or substituted by one or more groups selected from halogen, methyl and methoxy, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkoxy, aryloxy, arylC1-8alkoxy, C1-8 alkoxycarbonyl, aryloxycarbonyl, C1-8 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, C1-8 alkanoylamino, aroylamino, C1-8 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom is oxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, alkoxycarbonylamino, aryloxycarbonylamino, alkylcarbamoyloxy, arylcarbamoyloxy, alkylsulfonylamino, arylsulfonylamino, alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino; R_(h) is selected from the group consisting of C1-8 alkyl, aryl, C1-8 alkoxycarbonyl, aryloxycarbonyl, arylC1-8alkoxycarbonyl, carbamoyl wherein the nitrogen atom is unsubstituted or mono or di-substituted with a group selected from C1-8 alkyl, C3-7 cycloalkyl, aryl, arylC1-8alkyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl and heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, tetrazolyl, thiadiazolyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolyl, isoindolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, purinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenothiazinyl and phenoxazinyl, halogen, hydroxy, carboxy and cyano; and X is O or S.
 3. The compound according to claim 2 wherein: R₁ is C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl, indolinyl, pyranyl and thiopyranyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl; wherein R₁ is unsubstituted or substituted by one or more R_(b); R_(b) is selected from the group consisting of C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-8 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(b) is unsubstituted or substituted by one or more R_(c); R_(c) is selected from the group consisting of C1-5 alkyl, C3-6 cycloalkyl, aryl, C1-5 alkoxy, aryloxy, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino; R₂ is H or C1-3 alkyl; R₃ is H, C1-5 alkyl, C3-7 cycloalkyl or aryl wherein R₃ is unsubstituted or substituted by one or more R_(d); R_(d) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, C1-5 alkanoyl, aroyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(d) is unsubstituted or substituted by one or more R_(e); R_(e) is selected from the group consisting of C1-5 alkyl, C3-6 cycloalkyl, aryl, arylalkyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, aroyl, amino, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino; R₄ is H or C1-3 alkyl; R₅ is H or C1-8 alkyl; R₆ is C1-5 alkyl, C3-7 cycloalkyl, aryl or cyano, wherein R₆ is unsubstituted or substituted by one or more R_(f); R_(f) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, heteroarylC1-5alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or substituted independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylC1-5 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino, R_(f) is unsubstituted or substituted by one or more R_(g); R_(g) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, aryl unsubstituted or substituted by one or more groups selected from halogen, methyl and methoxy, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, arylC1-5 alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, oxo, carboxy, cyano, nitro, amidino and guanidino; R_(h) is selected from the group consisting of C1-5 alkyl, aryl, C1-5 alkoxycarbonyl, aryloxycarbonyl, arylC1-5alkoxycarbonyl, carbamoyl wherein the nitrogen atom is unsubstituted or mono or di-substituted with a group selected from C1-5 alkyl, C3-7 cycloalkyl, aryl, arylC1-5alkyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, and heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, halogen, hydroxy, carboxy and cyano.
 4. The compound according to claim 3 wherein: Y is O; R₁ is C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl, pyranyl and thiopyranyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl; wherein R₁ is unsubstituted or substituted by one or more R_(b); R_(b) is selected from the group consisting of C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxy, aryloxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by alkyl or aryl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl, or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy, cyano and nitro, R_(b) is unsubstituted or substituted by one or more R_(c); R_(c) is selected from the group consisting of C1-5 alkyl, C3-6 cycloalkyl, aryl, C1-5 alkoxy, aryloxy, halogen, hydroxy, oxo, carboxy and cyano; R₂ is H or methyl; R₃ is H, C1-5 alkyl, C3-7 cycloalkyl or phenyl wherein R₃ is unsubstituted or substituted by one or more R_(d); R_(d) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxy, aryloxy, aroyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano, R_(d) is unsubstituted or substituted by one or more R_(e); R_(e) is selected from the group consisting of C1-5 alkyl, C3-6 cycloalkyl, aryl, arylC1-5alkyl, C1-5 alkoxy, aryloxy, arylC1-3alkoxy, aroyl, amino, halogen, hydroxy, oxo, carboxy and cyano; R₄ is H or methyl; R₅ is H or C1-5 alkyl; R₆ is C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl or cyano, wherein R₆ is unsubstituted or substituted by one or more R_(f); R_(f) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, heteroarylC1-5alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylC1-5 alkylthio wherein the sulfur atom unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano, R_(f) is unsubstituted or substituted by one or more R_(g); R_(g) is selected from the group consisting of C1-5 alkyl, C3-7 cycloalkyl, phenyl unsubstituted or substituted by one or more groups selected from halogen, methyl and methoxy, naphthyl unsubstituted or substituted by one or more groups selected from halogen, methyl and methoxy, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, piperazinyl and indolinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, pyridinyl, pyrimidinyl, pyrazinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl, isoquinolinyl, quinazolinyl and quinoxalinyl, C1-5 alkoxy, aryloxy, arylC1-5alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl, aryl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano; R_(h) is selected from the group consisting of C1-5 alkyl, phenyl, naphthyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, arylC1-3alkoxycarbonyl, carbamoyl wherein the nitrogen atom is unsubstituted or mono or di-substituted with a group selected from C1-5 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, arylC1-3alkyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl and heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, carboxy and cyano; and X is O.
 5. The compound according to claim 4 wherein: R₁ is C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl, piperazinyl, pyranyl and thiopyranyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, wherein R₁ is unsubstituted or substituted by one or more R_(b); R_(b) is selected from the group consisting of C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-3 alkoxy, phenoxy, C1-3 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl, phenyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by C1-5alkyl, phenyl or naphthyl; C1-5 alkoxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano, R_(b) is unsubstituted or substituted by one or more R_(c); R_(c) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, aryl, C1-3 alkoxy, phenoxy, halogen, hydroxy, oxo, carboxy and cyano; R₂ is H; R₃ is C1-5 alkyl, C3-6 cycloalkyl or phenyl, wherein R₃ is unsubstituted or substituted by one or more R_(j); R_(d) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, quinolinyl and isoquinolinyl, C1-5 alkoxy, phenoxy, aroyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, C1-5 alkanoylamino, aroylamino, C1-3 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, phenylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by C1-3 alkyl, phenyl or heteroaryl selected the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, C1-5 alkoxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-3 alkyl, phenyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl, halogen, hydroxy, oxo, carboxy and cyano, R_(d) is unsubstituted o r substituted by one or more R_(e); R_(e) is selected from the group consisting of C1-5 alkyl, C5-6 cycloalkyl, phenyl, naphthyl, arylC1-3alkyl, C1-5 alkoxy, phenoxy, arylC1-3alkoxy, aroyl, amino, halogen, hydroxy, oxo, carboxy and cyano; R₄ is H; R₆ is C1-5 alkyl, C3-6 cycloalkyl, phenyl or cyano, wherein R₆ is unsubstituted or substituted by one or more R_(f); R_(f) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-5 alkoxy, aryloxy, arylC1-3alkoxy, heteroarylC1-3alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl, phenyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, and indolyl, C1-5 alkanoylamino, aroylamino, C1-3 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylC1-3alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by C1-5 alkyl or phenyl, C1-5 alkoxycarbonylamino, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, indolyl, halogen, hydroxy, oxo, carboxy and cyano, R_(f) is unsubstituted or substituted by one or more R_(g); R_(g) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, phenyl unsubstituted or substituted by one or more groups selected from halogen and methyl, heterocyclyl selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl and piperazinyl, heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl, pyrimidinyl, pyrazinyl and indolyl, C1-5 alkoxy, aryloxy, arylC1-3alkoxy, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl or aryl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by C1-5 alkyl or aryl, C1-5 alkoxycarbonylamino, aryloxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-5 alkylsulfonylamino, arylsulfonylamino, C1-5 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl or aryl, halogen, hydroxy, oxo, carboxy and cyano; R_(h) is selected from the group consisting of C1-5 alkyl, phenyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, arylC1-3alkoxycarbonyl, carbamoyl wherein the nitrogen atom is unsubstituted or mono or di-substituted with a group selected from C1-5 alkyl, C3-6 cycloalkyl, phenyl, naphthyl and arylC1-3alkyl; halogen, hydroxy, carboxy and cyano.
 6. The compound according to claim 5 wherein: R₁ is C5-6 cycloalkyl, phenyl, naphthyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl, piperazinyl, pyranyl and thiopyranyl or heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyridinyl and indolyl wherein R₁ is unsubstituted or substituted by one or more R_(b); R_(b) is selected from the group consisting of C5-6 cycloalkyl, phenyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl, imidazolyl, tetrazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, C1-3 alkoxy, C1-3 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-3 alkyl, phenyl or heteroaryl selected from the group consisting of pyrrolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl and benzthiazolyl C1-5 alkanoylamino, aroylamino, C1-3 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, arylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by C1-3alkyl or phenyl, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-3alkyl, phenyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl or heteroaryl selected from the group consisting of pyrrolyl, imidazolyl, pyridinyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, quinolinyl and isoquinolinyl, halogen, hydroxy, oxo, carboxy and cyano, R_(b) is unsubstituted or substituted by one or more R_(c); R_(c) is selected from the group consisting of C1-3 alkyl, C5-6 cycloalkyl, C1-3 alkoxy, halogen and hydroxy; R₃ is C1-5 alkyl, C5-6 cycloalkyl or phenyl wherein R₃ is unsubstituted or substituted by one or more R_(d); R_(d) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, 4-piperidinyl, 4-morpholinyl, piperazinyl, furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, C1-5 alkoxy, phenoxy, aroyl, C1-5 alkoxycarbonyl, aryloxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl or phenyl, C1-5 alkanoylamino, C1-3 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by C1-3 alkyl or phenyl, C1-5 alkoxycarbonylamino, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-3 alkyl or phenyl, halogen, hydroxy, oxo, carboxy and cyano, R_(d) is unsubstituted or substituted by one or more R_(e); R_(e) is selected from the group consisting of C1-5 alkyl, C5-6 cycloalkyl, phenyl, benzyl, C1-5 alkoxy, phenoxy, benzyloxy, aroyl, halogen, hydroxy, oxo, carboxy and cyano; R₅ is H or C1-3alkyl; R₆ is C1-5 alkyl, phenyl or cyano, wherein R₆ is unsubstituted or substituted by one or more R_(f); R_(f) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, C1-3 alkoxy, benzyloxy, pyridylC1-3alkoxy, thienylC1-3alkoxy, furanylC1-3alkoxy, C1-3 alkoxycarbonyl, phenoxyoxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-3 alkyl or phenyl, C1-5 alkanoylamino, aroylamino, methylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by C1-5 alkyl or phenyl, C1-3 alkoxycarbonylamino, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl or phenyl, halogen, hydroxy, oxo, carboxy and cyano, R_(f) is unsubstituted or substituted by one or more R_(g); R_(g) is selected from the group consisting of C1-3 alkyl, phenyl unsubstituted or substituted by one or more groups selected from the group consisting of halogen and methyl, heterocyclyl selected from the group consisting of piperidinyl, morpholinyl and piperazinyl; heteroaryl selected from the group consisting of furanyl, thienyl, pyrrolyl and pyridinyl, C1-3 alkoxy, aryloxy, benzyloxy, C1-5 alkoxycarbonyl, C1-5 alkanoyloxy, aroyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl or phenyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, ureido wherein either nitrogen atom is unsubstituted or independently substituted by C1-5 alkyl or phenyl, C1-5 alkoxycarbonylamino, C1-5 alkylcarbamoyloxy, arylcarbamoyloxy, C1-3 alkylsulfonylamino, arylsulfonylamino, C1-3 alkylaminosulfonyl, arylaminosulfonyl, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-3 alkyl or phenyl, halogen, hydroxy, oxo, carboxy and cyano; R_(h) is selected from the group consisting of C1-3 alkyl, phenyl, C1-3 alkoxycarbonyl, phenoxyoxycarbonyl, benzyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or mono or di-substituted with a group selected from C1-5 alkyl, phenyl and benzyl, halogen, hydroxy, carboxy and cyano.
 7. The compound according to claim 6 wherein: R₁ is C5-6 cycloalkyl, phenyl, naphthyl, piperidinyl, morpholinyl, piperazinyl, pyranyl, thiopyranyl, furanyl, thienyl or pyrrolyl wherein R₁ is unsubstituted or substituted by one or more R_(b); R_(b) is selected from the group consisting of C5-6 cycloalkyl, phenyl, furanyl, thienyl, pyrrolyl, imidazolyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, C1-3 alkoxy, C1-3 alkoxycarbonyl, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-3 alkyl or phenyl; C1-5 alkanoylamino, aroylamino, ureido wherein either nitrogen atom is unsubstituted or independently substituted by C1-3alkyl or phenyl; C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-3alkyl or phenyl, halogen, hydroxy, oxo, carboxy and cyano, R_(b) is unsubstituted or substituted by one or more R_(c); R_(c) is selected from the group consisting of C1-3alkyl, C1-3alkoxy, halogen and hydroxy; R₃ is C1-5 alkyl, C5-6 cycloalkyl or phenyl, wherein R₃ is unsubstituted or substituted by one or more groups of the formula R_(d); R_(d) is selected from the group consisting of C1-3 alkyl, C3-6 cycloalkyl, phenyl, naphthyl, 4-piperidinyl, furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, C1-3 alkoxy, C1-5 alkoxycarbonyl, C1-5 alkanoyloxy, benzoyloxy, carbamoyl wherein the nitrogen atom is unsubstituted or substituted independently mono or di-substituted by C1-3 alkyl or phenyl, C1-5 alkanoylamino, C1-3 alkylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, C1-3 alkoxycarbonylamino, C1-3 alkylsulfonylamino, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-3 alkyl or phenyl, halogen, hydroxy, oxo, carboxy and cyano, R_(d) is unsubstituted or substituted by one or more R_(e); R_(e) is selected from the group consisting of C1-3 alkyl, phenyl, benzyl, C1-3 alkoxy, phenoxy, benzyloxy, benzoyl, halogen, hydroxy, oxo, carboxy and cyano; wherein the configuration at the stereocenter defined by R₂ and R₃ and the carbon they arc attached to is defined as L; R₅ is H or methyl; R₆ is C1-5 alkyl, phenyl or cyano wherein R₆ is unsubstituted or substituted by one or more groups of the formula R_(f); R_(f) is selected from the group consisting of methyl, C3-6 cycloalkyl, phenyl, naphthyl, furanyl, thienyl, thiazolyl, imidazolyl, pyridinyl, indolyl, C1-3 alkoxy, benzyloxy, pyridylC1-3alkoxy, thienylC1-3alkoxy, furanylC1-3alkoxy, C1-5 alkanoylamino, aroylamino, methylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, C1-3 alkoxycarbonylamino, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-5 alkyl or phenyl, halogen, hydroxy, oxo, carboxy and cyano, R_(f) is unsubstituted or substituted by one or more R_(g); R_(g) is selected from the group consisting of C1-3 alkyl, phenyl unsubstituted or substituted by one or more groups selected from halogen and methyl, C1-3 alkoxy, aryloxy, benzyloxy, C1-3 alkoxycarbonyl, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-3 alkyl or phenyl, C1-5 alkanoylamino, aroylamino, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-3 alkyl or phenyl, halogen, hydroxy, oxo, carboxy and cyano; R_(h) is selected from the group consisting of C1-3 alkyl, phenyl, C1-3 alkoxycarbonyl, benzyloxy and carboxy.
 8. The compound according to claim 7 wherein: R₁ is cyclohexyl, phenyl, naphthyl, piperidinyl, morpholinyl, piperazinyl, pyranyl or thiopyranyl wherein R₁ is unsubstituted or substituted by one or more R_(b); R_(b) is selected from the group consisting of C5-6 cycloalkyl, phenyl, furanyl, thienyl, pyrrolyl, imidazolyl, indolyl, benzofuranyl, benzothienyl, benzimidazolyl, benzthiazolyl, C1-3 alkoxy, C1-3 alkoxycarbonyl, carbamoyl wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-3 alkyl or phenyl, C1-5 alkanoylamino, aroylamino, C1-5 alkylsulfonylamino, arylsulfonylamino, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-3 alkyl, halogen, hydroxy, oxo, carboxy and cyano, R_(b) is unsubstituted or substituted by one or more R_(c); R_(c) is selected from the group consisting of C1-3 alkoxy, halogen and hydroxy; R₃ is C1-5 alkyl or C5-6 cycloalkyl wherein R₃ is unsubstituted or substituted by one or more R_(d); R_(d) is selected from the group consisting of methyl, C3-6 cycloalkyl, phenyl, naphthyl, thienyl, imidazolyl, pyridinyl, indolyl, C1-4 alkoxy, C1-5 alkanoylamino, methylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, halogen, hydroxy, oxo, carboxy and cyano, R_(d) is unsubstituted or substituted by one or more R_(e); R_(e) is selected from the group consisting of methyl, phenyl, benzyl, methoxy, phenoxy, benzyloxy, benzoyl, halogen and hydroxy; R₆ is C1-5 alkyl or phenyl, wherein R₆ is unsubstituted or substituted by one or more R_(f); R_(f) is selected from the group consisting of C3-6 cycloalkyl, phenyl, naphthyl, thienyl, imidazolyl, pyridinyl, indolyl, methoxy, benzyloxy, C1-3 alkanoylamino, methylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, methoxycarbonylamino, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-3 alkyl, halogen, hydroxy, carboxy and cyano, R_(f) is unsubstituted or substituted by one or more R_(g); R_(g) is selected from the group consisting of methyl, phenyl unsubstituted or substituted by one or more groups selected from halogen and methyl, methoxy, phenoxy, benzyloxy, methoxycarbonyl, amino wherein the nitrogen atom is unsubstituted or substituted independently mono or di-substituted by C1-3 alkyl or phenyl, halogen, hydroxy and carboxy; R_(h) is selected from the group consisting of vinyl, phenyl, methoxycarbonyl, benzyloxycarbonyl and carboxy.
 9. The compound according to claim 8 wherein: R₁ is cyclohexyl, phenyl, naphthyl, piperidinyl, morpholinyl, piperazinyl, pyranyl or thiopyranyl, wherein R₁ is unsubstituted or substituted by one or more R_(b); R_(b) is selected from the group consisting of pyrrolyl, imidazolyl, indolyl, benzimidazolyl, methoxy, methoxycarbonyl, amino wherein the nitrogen atom is unsubstituted or independently mono or di-substituted by C1-3 alkyl, halogen, hydroxy and carboxy, R_(b) is unsubstituted or substituted by one or more R_(c); R_(c) is selected from the group consisting of methoxy, halogen and hydroxy; R_(d) is selected from the group consisting of methyl, C3-6 cycloalkyl, phenyl, naphthyl, C1-4 alkoxy, C1-3 alkanoylamino, methylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, halogen, hydroxy, oxo, carboxy and cyano, R_(d) is unsubstituted or substituted by one or more R_(e); R_(e) is selected from the group consisting of methyl, phenyl, methoxy, halogen and hydroxy; R₅ is H; R_(f) is selected from the group consisting of C5-6 cycloalkyl, phenyl, naphthyl, thienyl, indolyl, methoxy, benzyloxy, methylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, methoxycarbonylamino, halogen, hydroxy, carboxy and cyano, R_(f) is unsubstituted or substituted by one or more R_(g); R_(g) is selected from the group consisting of methyl, phenyl unsubstituted or substituted by halogen, methoxy, phenoxy, benzyloxy, methoxycarbonyl, halogen, hydroxy and carboxy; R_(h) is vinyl or phenyl.
 10. The compound according to claim 9 wherein: R₁ is phenyl, naphthyl or 4-morpholinyl wherein R₁ is unsubstituted or substituted by one or more R_(b); R_(b) is selected from the group consisting of benzimidazolyl, methoxy and dimethylamino R_(b) is unsubstituted or substituted by R_(c) wherein R_(c) is a halogen atom; R₃ is C1-5 alkyl wherein R₃ is unsubstituted or substituted by one or more R_(d); R_(d) is selected from the group consisting of C3-6 cycloalkyl, phenyl or naphthyl, R_(d) is unsubstituted or substituted by one or more R_(e); R_(e) is selected from the group consisting of methyl and halogen, R_(f) is selected from the group consisting of C5-6 cycloalkyl, phenyl, naphthyl, indolyl, benzyloxy, methylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, benzylthio wherein the sulfur atom is unoxidized or oxidized to a sulfoxide or sulfone, halogen and carboxy, R_(f) is unsubstituted or substituted by one or more R_(g); R_(g) is selected from the group consisting of methyl, methoxy, methoxycarbonyl, halogen and hydroxy.
 11. A method of making a compound of the formula(II):

wherein A is —C(O)—, X is O, and R₂, R₃ R₄, R₅ and R₆ are as defined in claim 1; comprising: a) reacting a protected amino acid with a protecting group R′ with an amide compound possessing R₆, said reaction taking place under coupling conditions consisting essentially of EDC, HOBT and a solvent select from DMF and methylene chloride;

b) removing the protecting group R′ from the compound produced in step a); c) reacting the compound produced from step b) with an acid chloride according to the formula below:

wherein X′ is CONH₂ and R₁ is as defined in claim 1; and d) dehydrating the amide compound produced in step c) with a dehydrating agent in cyanuric chloride and DMF to produce the nitrite compound of the formula(II).
 12. A compound selected from the group consisting of:

N-(4-morpholinecarbonyl)-L-(4-methyl)leucine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-(4-methyl)leucine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2R-benzyloxypropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(benzylsulfanyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(2-chlorophenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(4-chlorophenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(3-methoxyphenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-(4-methyl)leucine (1R-cyano-2-(benzylsulfanyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(benzylsulfonyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(benzylsulfinyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-((4-methoxyphenyl)methylsulfanyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(3-chlorophenyl)methyloxyethyl)amide;

N-(5-dimethylaminonaphth-1-ylsulfonyl)-L-leucine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(2-methylphenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(3-methylphenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(4-methylphenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(3-carbomethoxyphenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1R-cyano-2-(4-carbomethoxyphenyl)methyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-3-(carbo-t-butoxy)propyl)amide;

N-(4-morpholylinecarbonyl)-L-leucine (1S-cyano-3-phenylpropyl)amide;

N-(4-Morpholinecarbonyl)-L-leucine [1S-cyano-5-((benzyloxycarbonyl)-amino)pentyl]amide;

N-(4-morpholinecarbonyl)-L-cyclohexylalanine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-cyclohexylalanine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-nor-leucine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-(2-naphthyl)alanine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-(2-chlorophenyl)alanine (1S-cyano-3-phenylpropyl)amide;

N-Benzoyl-L-leucine (1R-cyano-2-benzyloxyethyl)amide;

N-(4-morpholinecarbonyl)-L-(O-methyl)tyrosine (1S-cyano-3-phenylpropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine(1S-cyano-2-(carbobenzyloxy)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-1-phenylmethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1-cyanocyclopropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-(2-chlorophenyl)ethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-3-(carbobenzyloxy)propyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S,3-dicyanopropyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S,2-dicyanoethyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-3-(methylsulfonyl)propyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-3-(4-hydroxyphenyl)propyl)amide;

N-(4-morpholinecarbonyl)-L-leucine (1S-cyano-2-cyclohexylethyl)amide and the pharmaceutically acceptable salts, esters, tautomers, individual isomers and mixtures of isomers thereof.
 13. A method of treating an autoimmune disease, said method comprising administering to a patient in need of such treatment a pharmaceutically effect amount of a compound according to claims 1 or
 12. 14. The method according to claim 13 wherein the autoimmune disease is selected from the group consisting of: rheumatoid arthritis, systemic lupus erythematosus, Crohn's disease, ulcerative colitis, multiple sclerosis, Guillain-Barre syndrome, psoriasis, Grave's disease, myasthenia gravis, scleroderma, glomerulonephritis, atopic dermatitis and insulin-dependent diabetes mellitus.
 15. A method of treating Alzheimer's disease comprising administering to a patient in need of such treatment a pharmaceutically effective amount of a compound according to claims 1 or
 12. 16. A method of treating atherosclerosis comprising administering to a patient in need of such treatment a pharmaceutically effective amount of a compound according to claims 1 or
 12. 17. A pharmaceutical composition comprising a pharmaceutically effective amount of a compound according to claims 1 or
 12. 